DE69029443T2 - Ink jet recording apparatus - Google Patents

Abstract

An ink jet recording apparatus (100) includes a recording device (9) for depositing ink onto a recording medium (40) with relative movement therebetween to effect recording on the recording medium; a shaft (51) engageable with a part of the recording device and rotatable about an eccentric axis; and a member (51c) for supporting the shaft adjacent longitudinal ends thereof for eccentric rotation of the shaft to change relative positional relation between the recording device and the recording medium.

Description

FIELD OF THE INVENTION AND STATE OF THE ART

The present invention relates to an ink jet recording apparatus according to the preamble of claims 1 and 5, respectively, and more particularly to a small-sized ink jet recording apparatus having an adjusting mechanism for adjusting the gap between a recording head and a recording medium.

The ink jet recording apparatus includes not only the elements directly related to the recording operation but also various elements peculiar to the ink ejection type recording.

When the ejection of liquid is not performed for a long period of time at a certain ejection outlet or outlets depending on the type of data to be recorded or when the recording apparatus is not used for a long period of time, the water content of the ink in the ejection outlet or in the ink pipe communicating with the ejection outlets evaporates so that the viscosity of the ink is increased. This may result in failure of ink ejection. When a droplet or droplets of ink or water or foreign matter are deposited on a surface on which the ejection outlets are formed, the ejected ink droplet is affected by the deposited material, resulting in the deflection of the ink ejection direction. To avoid these problems, the ink jet recording apparatus is equipped with various components for so-called ejection recovery to restore the To prevent failure of ejection or deviation of the ejection direction.

In order to prevent the failure of ejection, the ejection recovery system includes a structure for pre-ejecting the ink to eject ink having high viscosity onto an ink receiving material, a structure for sucking the ink through the ejection outlet or an ink chamber to remove the ink having high viscosity, and a structure for covering the ejection side surface to prevent evaporation of the water content of the ink through the ejection outlets.

In order to prevent the deviation of the ejection direction, there is a structure for wiping the ejection side surface to remove the foreign matter or the ink droplets deposited near the ejection opening.

Recently, it has become common for the ink jet recording apparatus to perform recording on various recording media such as common paper envelopes. To meet this requirement, a special construction is used which responds to the various thicknesses of the recording media.

In particular, the gap between the recording head and the recording medium is adjusted during the recording process by an adjusting mechanism to provide an appropriate gap in accordance with the recording medium used.

On the other hand, recently, the ink jet recording device including the recording head is manufactured by a thin film process or by micro-system technology as in the manufacture of semiconductor chips, and therefore, a recording head of small size and low cost is being manufactured. Accordingly, a disposable type recording head having, for example, an integrally molded ink tank has been proposed. In some circumstances, a device of small size and low cost which is easily used by users is desired.

However, the reduction in the size of the apparatus requires the reduction in the sizes of various parts and the reduction in the space for arranging and operating the various essential components. As a result, it is desirable that the structures of these components or of other components and the structures among them be different from those in relatively large apparatuses.

In order to effect good recording in the ink jet recording apparatus, it is desirable that the movement of the recording head be parallel to a recording medium.

Traditionally, the adjustment of the parallel movement is carried out on the carrier (slide) that carries the recording head.

However, the conventional adjustment mechanism has a complicated structure that requires difficult operation. This hinders the reduction in the size of the device.

In addition, the adjustment may change the relative positional relationship between the recording head and an ink suction cap or a wiping blade, so that the performance of the suction action or the wiping action is deteriorated.

On the other hand, it is considered that in accordance with the recording medium, particularly with the thickness of the recording medium, the recording head is rotated about an axis to ensure an appropriate gap between the recording medium and the ejection outlet of the recording head. With the appropriate gap, the size and the like of the image formed by the ink droplets will be appropriate.

In the conventional construction, a rotary cam or the like is provided on the recording head or a carrier, and therefore the mechanism is complicated and bulky in many cases.

In addition, a rotary lever or other actuating member is usually mounted on the recording head or fixed on the substrate, and therefore the operation thereof is rather complicated, particularly in a small-sized recording device. In addition, there is a problem that the positional relationship is changed with a recovery mechanism.

In this context, document DE-A-3 528 926, which forms the preamble of claims 1 and 5, respectively, discloses an ink jet printer using a print head which is movable relative to a sheet supporting member. On one side of the sheet supporting member there is arranged an ink recovery and capping mechanism which comprises a cleaning blade and which can be moved relative to the print head. In operation, the print head is movable relative to a recording sheet arranged on the sheet supporting member to effect recording on the recording sheet in a recording area, while it is movable to the outside of the recording area to face the ink recovery and capping mechanism when no recording is to be performed.

Although the known ink recovery and capping mechanism serves to reliably cause correct ejection of ink droplets from the print head, this prior art suffers from the fact that, depending on the thickness of the recording medium to be printed, the position and size of the characters formed from the ink droplets ejected from the print head onto the recording medium differ considerably, since the gap between the recording head and the recording medium varies with the thickness of the recording medium.

SUMMARY OF THE INVENTION

Accordingly, it is the object of the invention to further develop the known ink jet recording device in such a way that the gap between the recording head and the recording medium is made to have a high Accuracy can be adjusted while the cleaning process of the recording head is carried out in a reliable manner.

This object is achieved by the features set out in the characterizing sections of patent claims 1 and 5, respectively.

According to claim 1, the ink jet recording device comprises an axis engageable with a portion of the recording means and rotatable about an eccentric axis to change the positional relationship between the recording means and the recording medium. The axis has an eccentric portion to allow a gap between the recording means and the recording medium to be changed in the recording area. Furthermore, the ink jet recording device comprises another axis for maintaining a predetermined positional relationship between the recording means and the recovery means outside the recording area, regardless of the gap between the recording means and the recording medium in the recording area.

According to claim 5, the ink jet recording apparatus comprises a moving means for moving the recovery means and the axis for guiding the carriage carrying the recording means in one to adjust a gap between the recording means and the recording medium, thereby keeping the positional relationship between the recording means and the recording medium constant, regardless of the positional relationship between the latter and the recording medium.

As a result, according to the invention, the gap between the recording means and the recording medium can be adjusted with high accuracy regardless of the positional relationship between the recording means and the recovery means. Conversely, however, the distance between the recovery means and the recording means can be kept constant, namely regardless of the gap between the latter and the recording medium.

Advantageously developed embodiments of the invention are the subject of the dependent patent claims 2 to 4 and 6 to 8.

The features and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, which is given in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an axonometric view of an ink-jet recording apparatus according to an embodiment of the present invention, showing the external appearance thereof.

Fig. 2 is an axonometric view of the device of Fig. 1, showing the main part of the device without a cover.

Fig. 3A is an axonometric view of the device of Fig. 1 showing a sheet ejection system.

Fig. 3B is a side view of the sheet ejection system of Fig. 3A.

Figs. 4A and 4B are side views showing the different positions of a recording head with respect to different recording materials.

Fig. 5A and 5B are rear views of the recording head in its home position in different states.

Fig. 6 is a partially broken away axonometric view of a base for a recovery system mechanism engaging a base frame.

Figs. 7A, 7B and 7C are axonometric views showing a recording head wiping sheet and an ink carrier.

Figs. 8 and 9 are an axonometric exploded view and a cross-section, respectively, of a suction and recovery system for the recording head.

Fig. 10 is a timing diagram of the operations of the individual parts of the device according to this embodiment.

Fig. 11 is an axonometric view of a clutch mechanism for transmitting a driving force to the recovery system mechanism in the device of this embodiment.

Figs. 12A, 12B and 12C are side views showing the engagement between the clutch gear of Fig. 11, a hook and a control gear.

Figs. 13A and 13B are front views showing the engagement between the clutch gear, the hook and the control gear shown in Figs. 12A, 12B and 12C.

Figs. 14A, 14B, 14C and 14D are side views showing the sequential operations of the blade and the ink carrier.

Figs. 15A, 15B and 15C are side views showing the sequential actuations of a cap.

Figures 16A and 16B are side sections showing an operation of a pump for a recovery priming operation.

Fig. 17 is a timing chart showing the sequential operations of a pre-discharge operation or a suction recovery operation in the device of the embodiment and partly of another embodiment.

Figures 18A and 18B are side views of a blade containment mechanism.

Fig. 19 is an axonometric view of a spur wheel in a blade ejection system.

Fig. 20 is a front view of a sheet ejection roller.

Fig. 21 is an axonometric view of a device according to a variant of the present invention used in another position.

Fig. 22 is a side section of the device arranged as shown in Fig. 21.

Fig. 23 is an axonometric view showing the external appearance of the recording head.

Figs. 24A and 24B are an exploded axonometric view and an axonometric view of the external appearance of a recording head, respectively.

Figs. 25A, 25B and 25C are a top view, a left side view and a right side view of a carrier (slide).

Figs. 26A and 26B are a top view and a right side view of the carrier shown in Figs. 25A, 25B and 25C when it carries the recording head.

Fig. 27 is a top view of the carrier before the recording head is mounted on it.

Figs. 28A, 28B and 28C are top views of the carrier when the recording head is mounted thereon.

DESCRIPTION OF THE PREFERRED DESIGN VARIANTS

Referring to the accompanying drawings, the preferred embodiments of the invention will now be described.

Referring to Fig. 1, there is shown an ink jet recording apparatus 100 according to an embodiment of the present invention. The apparatus 100 is selectively used in a generally horizontal position as shown in Fig. 1 or in a vertical position as will be described hereinafter. The apparatus 100 is small and lightweight.

The device 100 includes a housing 101, an outer cover 102 and an inner cover 103. When the device 100 is not in use, the outer cover 102 covers the inner cover 103 and therefore the device is compact. The user can put the device in a dedicated housing and can carry it around.

When the device 100 is used in the horizontal position as shown in this figure, the part indicated by reference numeral 106 serves as the inlet for the recording material. The outer cover 102 can be used as an ejection basket.

In each of the above cases, the part designated by a reference numeral 107 serves as a sheet ejection outlet.

A positioning hook 105 serves to fix the position of the outer cover 102, and a reference numeral 104 designates the operating buttons and displays.

With reference to Fig. 2, the main part of the device will now be described.

The device comprises a base frame 1, a left side plate 1a serving as a guide for a recording medium such as paper, and a right side plate 1b. The base frame 1 is provided with an opening (not shown) for rotatably supporting the carrier motor, which will be described hereinafter.

A guide arm 1h is provided to support a guide screw 2 in the longitudinal and transverse directions. The guide screw 2 is rotatably supported in a bearing of the guide arm 1h. The guide arm 1h is fixedly attached to a recovery system base 50 by a plate not shown.

The guide screw 2 is provided with a guide groove 2a with a predetermined pitch facing a recording area. The guide screw 2 is provided on a side of the carrier home position with a positioning groove 3b for positioning at the time of a capping operation by a cap and an operation for correcting improper ink ejection and for preventing improper ejection. The positioning groove 3b is formed along a circumferential portion of the screw axis. The positioning groove 3b extends continuously and smoothly from the guide groove 2a via an introduction groove 3c.

The guide screw 2 has at its right end a shaft 2g which is coaxial with the guide screw 2, and has a shaft at its left side. The shafts are supported by bearings provided on a front part 1c of the side plate 1b and on the guide arm 1h, respectively. The shafts are rotatably supported by the bearings. A guide disk 3 is fixed on the guide screw 2, and is provided with the above-described grooves 3b and 3c and a pulley 3a at its end. The pulley 3a receives a driving force from a motor 11 via a timing belt 13.

The shaft 2g of the guide screw 2 is slidably engaged with a slot of the plate 1c serving as a guide plate connected to the right side plate 1b and the base frame 1. It is pushed in its pressing direction by a tongue 10a of a leaf spring 10, and it is engaged with a cam slot of a cam plate 50a rotatably supported on a pin on the guide plate 1c. Around the outer periphery of the cam plate 50a, engaging teeth are formed which are engageable with a ratchet 10c of the leaf spring 10, by which the cam plate 50a can be locked at a desired rotational position. By rotating and locking the cam plate 50a, the position in the slot of the guide plate 1c of the shaft 2g engaged with the cam slot is determined so that the position of the guide screw 2 at the right end is determined. This adjusting structure is used to adjust a gap between the recording head and the platen, which will be described later.

A clutch wheel 4 is supported for sliding movement in the longitudinal direction on the guide disk 3. It is fixed in the direction of rotation on the guide disk 3 by a driver which will be described later in connection with Fig. 11, so that the rotation of the guide screw 2 is transmitted to it. A clutch spring 5 is a compression spring for pressing the clutch wheel 4 toward the guide groove 2a. A limiting member is arranged between the clutch wheel 4 and the Guide disc 3 is arranged to limit the range of movement of the clutch wheel 4 in the axial direction within a predetermined range.

A carrier 6 is supported by the guide screw 2, and is movable along the length of the guide screw 2. The carrier 6 is provided with an operating portion for pressing an end face of the clutch gear 4, which is formed integrally with a left side of the carrier 6. The carrier 6 has a guide pin 7 which is engaged with the guide groove 2a of the guide screw 2, and which is guided along a guide hole (not shown) of the carrier 6 to communicate with the guide screw 2. A guide pin spring 8 has one end fixed to the carrier 6, and its other end presses the guide pin 7.

A recording head 9 is mounted on the substrate 6. In this embodiment, the recording head 9 is in the form of a cartridge which contains as a unit a recording head element 9a and an ink container 9b (ink supply source). The cartridge is detachably mounted on the substrate 6 and is discarded when the ink inside it is used up. Instead of the electrothermal transducer, an electro-mechanical transducer element is usable. The latter is preferable because in this case the ink ejection outlet can be manufactured with a high density and because the manufacturing process is simple.

A hook 6c is attached to a part of the carrier 6 to stably stop the recording head 9 at a capping location or the like.

A carrier guide shaft 51 is slidably engaged with a guide pin 6b formed at a rear end of the carrier 6. As will be described in connection with Fig. 4, the guide shaft 51 has an eccentric portion which is rotatably supported on the side plates 51b and 51c by a portion 51a of the shaft disposed at the opposite ends of the base frame 1. The portion 51a of the guide shaft 51 in the Near the side plate 51c is fixed to a positioning head 51d. The positioning head 51d is generally in the shape of a circular disk, and is provided substantially at its center with a leaf spring 51h in the form of a projection having a structure of a recess. The leaf spring 51h is formed by cutting out a part of the disk in the form of a channel. The portion 51a is fixed substantially at the center of the leaf spring 51h. The free end of the leaf spring 51h is provided with a projection 51i for fixing the rotational position of the knob 51d. The rotational position of the shaft 51 is fixed by the engagement between the projection 51i and the leaf spring 51h of the knob 51d and an opening 51e formed in the side plate 51c by means of the spring force of the leaf spring 51h.

As shown in Figs. 4A and 4B, this construction is used to adjust the gap between the recording surface of a recording sheet 40 and the ink ejection outlets of the recording head element 9a in accordance with the material of the recording sheet 40. Specifically, the knob 51d is manually rotated, whereby the distance between the shaft 51 and the pin 6b is minimum when the shaft 51 takes the position shown in Fig. 4A, and the distance can be maximum when the shaft 51 takes the position shown in Fig. 4B. By doing so, the recording head 9 rotates around the guide screw 2 so that the pitch can be fixed to suit a relatively thin, smooth paper (Fig. 4A) or a relatively thick recording paper such as envelopes (larger pitch as shown in Fig. 4B).

It should be noted that the above construction is designed to adapt to the materials of the recording sheet during the recording operation. The situation is different when the recording head 9 is moved to the recovery system at the left end of Fig. 2 when the recovery operation is to be carried out. In particular, at this time, the positional Relationship between the recording head 9 and the recovery system must be constant.

Figs. 5A and 5B show the structure for providing the constant positional relationship between the recording head and the recovery system during the recovery operation. Figs. 5A and 5B correspond to Figs. 4A and 4B. In Fig. 5A, the engagement between the portion 51a and the pin 6b is performed without a change in the height of the engagement position between the shaft 51 and the pin 6b. In order to maintain a constant height of the engagement position, one of the parallel surfaces of a trapezoidal cam 51g is engaged with the pin 6b.

In Fig. 5B, when the recording head 9 moves in the direction so that the pin 6b engages with the portion 51a, the height of the engagement position of the pin 6b changes. In consideration of this fact, the shaft 51 is provided with a tapered portion 51f, and accordingly the trapezoidal cam 51g has a tapered surface. Therefore, the height of engagement between the pin 6b and the shaft 51 is changed by the tapered portion 51f so that a constant height is maintained when the pin 6b engages with the portion 51a of the shaft.

With the above-described construction, when the recording head 9 comes to the ejection recovery system, the height of the recording head 9 is always constant, whereby the predetermined positional relationship between the recovery system and the recording head 9 can be maintained.

The number of rotational positions of the recording head 9 is not limited to two, but may be greater, with the intermediate positions matching a greater number of thicknesses of the recording paper. To accomplish this, the number of engagement positions between the projection of the knob 51d and the opening 51e of the side plate 51c may be increased.

The rotation of the knob 51d is not limited to manual rotation, but can also be automatically performed by rotating the knob 51d in response to a keyboard input according to the recording sheet to be used, for example, by using the driving force of a sheet feeding motor or the like.

Referring again to Fig. 2, a carrier motor 11 for driving the carrier 6 is formed, for example, in the form of a pulse motor. The left and right surfaces of the motor 11 are provided with pins 11a at mutually aligned positions. The pins 11a (the one on the right is not shown) are rotatably mounted in motor mounting holes of a recovery system base 50 which is movable on the base frame 1. It is a possible alternative that the pins are provided on the recovery system base 50 and that the holes are formed in the side of the motor. The carrier motor 11 is therefore rotatable about the pins 11a. A projection 11b extends integrally from the carrier motor 11 in parallel to the output shaft 12 of the motor. The projection 11b abuts against a motor spring 14. The projection 11b is provided with a column-like projection to which one end of the motor spring 14 is attached in the form of a screw.

A motor pulley is fixed to the output shaft 12 of the carrier motor 11. The timing belt 13 is stretched between the motor pulley and the pulley 3a fixed to the shaft of the guide screw 2. The motor spring 14 is in the form of a compression spring in this embodiment, and it is compressed between one end of the guide arm 1h and the spring receiving projection 11b of the carrier motor 11, whereby the carrier motor is pressed in a direction A to apply tension to the timing belt 13. Reference numeral 15 designates an adjusting shaft on which the recovery mechanism is fixed. The recovery mechanism comprises a means protruding from a side plate (not shown) fixed to the base 50 for maintaining a good condition of the To maintain the area forming the discharge outlet, the cap and the other means which contribute to the recovery and to the prevention of improper discharge.

As described above, the positional relationship between the recovery mechanism and the recording head 9 is important. In particular, the positional relationship between the surface of the recording head 9 on the ejection side and the blade for wiping the surface on the ejection side is important to maintain the desired wiping effect, and the distance between the cap and the surface on the ejection side is important to maintain the effect of the cap. In particular, it is desirable that the positional relationship between the recovery mechanism and the recording head be maintained.

On the other hand, the recording head 9 performs its recording operation while moving along the lead screw 2 by the driving force transmitted through the lead screw 2. During the recording operation, the distance between the recording sheet 40 and the recording head 9 is desirably the same regardless of the position of the recording head 9 in the moving range. Therefore, an adjusting mechanism is desirably provided to adjust the distance between the recording head 9 and the recording paper, thereby making the recording head slidable while maintaining parallelism with respect to the recording paper. However, such an adjusting mechanism may affect the constant positional relationship with the recovery system.

Accordingly, in this embodiment, the carrier motor 11, the recovery system base 50, which supports the recovery system, which will be described in detail below, and the guide screw 2 are movable with respect to the base frame 1.

The position of the guide screw 2 is adjusted at its opposite ends by moving the base 50 and by moving the cam plate 50a. By this adjustment, the recording head 9 is made movable parallel to the support which carries the recording sheet 40.

Referring to Fig. 6, a mechanism is shown in the base 50 to accomplish this. Fig. 6 is an axonometric view of the recovery system base 50 as viewed from the opposite side of Fig. 2, with it partially broken away. A guide member 50e is fixed to one side of a groove formed in a back of the base 50. A groove of the member 50e engages with a guide portion of a guide member 1k which is L-shaped and which is fixed to the base frame 1, thereby restricting the direction of movement of the base 50 and in addition preventing the base 50 from rising from the base frame 1.

As will be understood from Fig. 2, when the cam plate 50b is rotated about a pin 50d fixed to the base 50, the cam surface is engaged with a certain part of the surface of the cam slot 11 of the base frame 1 to press the contact surface. By doing so, the base 50 is moved by the reaction force in the direction guided by the link 50e and the link 1k.

The cam design may be modified so that the cam plate is rotated about a predetermined axis by operating a pin engageable with a cam slot formed in the cam plate.

The movement moves the support motor 11 on the base 50 and the drive system connected to the motor 11, in particular the timing belt 13, the pulleys and the guide screw 2, as well as the recovery system mechanism mounted on the base 50, thereby adjusting the position of the guide screw 2 on the recovery system side.

On the other hand, fine adjustment of the other end of the guide screw 2 is accomplished by rotating the cam plate 50a.

Through the above adjustment operations, the guide screw 2 is made parallel to the recording paper, and the recording head can be adjusted to move parallel to the recording sheet.

The adjustment operations are performed in this embodiment during the manufacturing of the recording device using an assembly robot. However, the adjustment operations may be performed by a user after the device has been used for a long period of time or at the time of other repair operations.

Referring now to Figs. 7A, 7B and 7C, also continuing to refer to Fig. 2, a description will now be given of the means for maintaining a good condition of the surface of the recording head on the ejection side, which is part of the recovery system.

In Fig. 7A, a blade lever 16 has a boss 16a rotatably mounted on an adjusting shaft 15. The blade lever 16 has an arm 16b and a hook 16c. A blade 17 serves to wipe the surface of the recording head on which the ink ejection outlets are formed. The blade is formed of silicone rubber, chloroprene rubber or a hydrogen-containing nitrile butadiene rubber or other elastic material. A blade shaft 18 clamps the blade 17 at its central portion in such a manner that the blade 17 extends parallel to the shaft 15. The blade shaft 18 is rotatably mounted on the blade lever 16. A rotatable member 18a is formed integrally with the blade shaft 18. An ink carrier 19 is made of a sintered plastic material such as urethane foam material or the like which is hydrophilic and porous, and is attached to the blade lever 16 at a position below the blade 17. The blade 17 and the blade carrier 19 are arranged in such a position that they overlap with the cap, which later described when viewed from the head member 9a so that they can act on the head member 9a in the same position. The positional overlapping relationship is advantageous because it can reduce the width of the device in the scanning direction.

An adjusting lever 20 is rotatably mounted on the adjusting shaft 15. The adjusting lever 20 is provided with stop teeth 20a and 20b, as well as a starting tooth 20c and a rotating tooth 20d. The starting tooth 20c has a thickness (measured in the longitudinal direction of the guide screw 2) that is approximately half the width of the other teeth. An arm 20e of the adjusting lever 20 is partially cut out in its thickness direction, thereby providing an adjusting surface 20f and a resetting surface 20g. The surfaces 20f and 20g act to provide a receptacle for the rotary member 18a of the blade spindle 18 mounted on the blade lever 16, in which the blade 17 is movable between a projecting position and a hanging position by the selective engagement of the rotary member 18a with the surface 20f or the surface 20g.

A steering wheel 21 is rotatably mounted on the base 50 by a support member not shown.

As shown in Fig. 7B, the control gear 21 is provided with a stop cam 21a for engaging with the stop teeth 20a and 20b of the adjustment lever 20 described above at a part of the circumference of the control gear 21. It is further provided with three drive teeth 21b1, 21b2 and 21b3 which are partially cut out. It is further provided with a cover cam 21c at a predetermined position for pivoting a cover lever which will be described later. It is further provided with a piston adjustment cam 21f for pressing a piston of a pump which will be described later. The piston adjustment cam 21f is in the form of an axially acting cam. Furthermore, a piston return cam 21g is provided at a predetermined distance from the piston adjustment cam 21f and corresponding thereto.

A spring 22 serves to support an ink absorbing material 23 and is fixed to the base 50 in the position shown in Fig. 2, i.e., at a position below the capping position of the cap. As shown in Fig. 7C, it has a portion 22a supporting an absorbing material and a spring 22b for rotating the pump, which will be described later. The ink absorbing material 23 is made of a material that is hydrophilic and porous, similarly to the ink carrier 19. The ink absorbing material 23 has a cleaning portion 23a with which the blade 17 is brought into contact when it moves downward. The lower portion of the ink absorbing material 23 is formed as a receiving surface with which the ink carrier 19 is contacted to transfer the ink. The portion of the holding spring 22 which carries the absorbing material is pushed upward by a small spring force so that it is locked at a predetermined position by a stopper not shown. Therefore, when the ink carrier 19 comes into contact with the ink absorbing material 23, the ink absorbing material 23 slides downward to bend the spring 22 of the ink absorbing material downward to ensure the contact between them.

Referring now mainly to Figs. 8 and 9, a description will be given of the recovery system unit which is a part of the recovery system mechanism. In Figs. 8 and 9, a cylinder 24 has a cylinder portion 24a and a guide portion 24b for guiding a piston shaft 27, which will be described later. The inner side of the guide portion 24b is partially cut away in its longitudinal direction to provide an ink pipe 24c for residual ink. A projection 24d serves to receive a cap lever and has a lever seal 33 engaged therewith. An ink pipe 24e opens into the cylinder portion 24a at a predetermined position. A rotatable lever 24f is formed integrally with the cylinder 24 and is urged in the rotational direction by the spring portion 22b of the spring 22 carrying the ink receiving member. A residual ink pipe 24g is formed integrally with the cylinder 24, and one end of it is cut off at an acute angle so that it can be easily inserted into a residual ink receiving material which will be described later. An ink pipe 24h is formed in the residual ink pipe 24g.

A cylinder cap 25 is press-fitted into one end of the cylinder 24. A lever guide 25a is arranged at a position opposite to the cap lever receiver 24d of the cylinder 24.

A piston seal 26 is fitted in the cylinder 24 and has a smaller inner diameter to exert a predetermined contact pressure with respect to the piston rod, which will be described below. Its surface may be coated with a lubricant to reduce the force required to slide the piston.

The piston rod 27 has an operating rod 27a, a piston limit collar 27b, a piston receiver 27c, a connecting rod 27d and a guide rod 27e. A groove 27f serving as an ink passage is formed along the connecting rod 27d and the guide rod 27e. A rotation stopper 27g is formed as a groove in the operating rod 27a. A bearing 27h is provided at one end of the operating rod 27a.

A piston 28 has a main portion as an inner layer when viewed from the side of the cylinder, which is made of an elastic and porous material. This may be a foam material (a sponge or the like) having independent pores, or a porous material having fine continuous pores. A porous material having continuous pores such as urethane foam is preferable. It may be such that a plurality of continuous pores exist in a direction crossing the direction of elastic deformation. The outer diameter of it is larger than the inner diameter of the cylinder 24 by a predetermined amount so that it is compressed to an appropriate extent when inserted into the cylinder 24. The foam material is oriented so that the solid (skin) layer of the material is on the outer peripheral surface 28a and on an end surface 28b which contacts the piston limiting collar 27b of the piston rod 27. Even if the material of the piston is of the continuous foam type, the skin film does not allow the fluids to communicate and therefore the skin film provides the function of the piston. If a material without a skin film is used, a coating layer may be provided.

A pump chamber is designated by a reference numeral 42. A piston pressure roller 29 is rotatably attached to one end of the piston rod 27. A piston return roller 30 is rotatably attached to the end of the piston rod 27. These rollers are mounted on a pin 31.

A cap lever 32 has a rotation axis 32a, an ink guide 32b and a lever guide 32c. At one end thereof, a sealing surface 32d is provided which is spherically convex. A cap lever 32 is provided with a vertical pair of engaging members 32e for engaging with claws of a cap holder 34. An ink pipe 32f extends from the sealing surface 32d through the inside of the lever 32, is deflected by 90º and passes through the center of the ink guide 32b. The pipe opens at its end. At a lower position of the ink guide 32b, a cut-off portion 32g is formed. The cut-off portion 32g serves to connect the ink line 24e to the inside of the cylinder 24a via a connecting hole 33a of the lever seal 33.

The lever seal 33 is mounted on the ink guide 32b and is press-fitted into the cap lever receptacle 24d. The connecting hole 33a provides a hydraulic connection between the cut-off portion 32g of the ink guide 32b and the ink line 24e.

The cap holder 34 is opposite a hook 34a for engaging with an engaging portion 32e of the cap lever 32. An opening 34b serves to attach the cap 35.

The cap 35 serves both to close the recording head so as to prevent the ink from drying out and to seal the recording head when the ink is sucked therefrom. The cap 35 has a cover portion in which a suction opening 35b is formed and therefore opens to the cap holder 34 through the center of the cap 35.

A flange 35c serves as a stopper when mounted on the cap holder. The flange 35c has a cap seal 35d which is spherically concave to correspond to the sealing surface 32d of the cap lever 32. When pressed onto the cap lever 32, only the central portion has a connection and the other portion is sealed. Since the seal portions 32d and 35d are spherical, they are excellently fitted to each other. The recording head element 9a has a step on the surface on the ejection side, and even if so, the cap can accommodate the step to ensure a stable sealing state.

Referring again to Fig. 2, a sheet conveying roller 36 is provided for conveying a recording medium such as paper or a sheet of paper. It may be made, for example, by applying an elastic ink (urethane resin or acrylic resin material) to the surface of a drawn aluminum tube. The roller 36 serves as a support for defining the area of the recording medium on which recording is carried out by its outer surface, and also serves to absorb the excess ink in its interior. The excess ink absorbing material 37 is inside the roller 36, and it comprises a thin tube made of a plastic material such as vinyl chloride or the like and polyester fibers, or other absorbent material to improve the ink absorption in the longitudinal direction. In the excess ink absorbing material 37, an excess ink tube 24g is formed. ink of the cylinder 24. Even when the recovery system mechanism is moved by the movement of the base 50, the tube 37 is held in the absorbing material 37 in such a manner as to prevent the movement. The fibers of the absorbing material are not liquid-absorbent such as resin or metal, but they may have a slightly liquid-absorbent property.

A blade containment plate 38 is made of, for example, fluorinated resin or a material to which carbon fibers are mixed. As shown in Fig. 3, it is divided into four sections which are fixed on the base frame 1. An axle 38A is provided to release the holding force to the containment plate 38. At one end of the axle 38A, a gear 38B is fixed, and the other end of it is engaged with a bearing 38C to support the axle 38A. The bearing 38C is fixed on the base frame 1. The gear 38B meshes with a gear of a release lever which is not shown. A sheet feed motor 39 is coupled to the sheet feed roller 36 via a reduction mechanism having a predetermined reduction ratio.

A reference number 40 designates a recording medium, such as paper or film.

The operation will now be described.

In a normal recording operation, the rotation of the shaft of the carrier motor 11 rotates the guide screw 2 via the control belt 13. The carrier 6 moves in the scanning direction through the engagement between the guide groove 2a and the guide pin 7. Since the carrier motor 11 is pressed by the motor spring 14, the control belt 13 is always tensioned to ensure good transmission of the driving force.

An inertia force exists due to the movement of the carrier 6 at the start and at the end, but the weight of the motor 11 absorbs the inertia force, so that the force exerted on the motor spring 14 is small. The load required on the motor 11 is also small. If an air damper or an oil cylinder is used in conjunction with the motor spring 14 is provided, the noise attributable to the vibration of the rotor of the motor at the start and stop of the carrier can be reduced. By appropriately selecting the weights of the motor and the carrier and the damping coefficient, overshoot of the motor can be reduced, so that the noise can be reduced.

Referring now to Figs. 10 and 16, the operation of the apparatus when the apparatus is not performing the recording operation will be described.

Fig. 10 is a timing chart, it will be understood that the operational timing of various parts can be determined based on the number of pulses sent to the motor.

Fig. 11 is an axonometric view showing the structure of the clutch wheel 4 and the control wheel 21. The keyway 4d of the clutch wheel 4 is engaged with the keyway 2h of the lead screw 2, whereby the clutch wheel is slidable on the lead screw while rotating together with the lead screw 2. The clutch wheel 4 is pressed by the spring 5 toward the carrier 6 so that it is in a predetermined position along the groove 2i of the lead screw 2 during the recording operation and rotates together with the lead screw 2. When the recording head 9 moves to the home position, the clutch wheel 4 is pressed by the carrier 6 so that it is engaged with the control wheel 21.

The clutch gear 4 has a start tooth 4c1 and drive teeth 4c2 formed at different positions of the clutch gear in its width direction. In addition, the drive teeth 4c2 are not formed uniformly over the entire circumference, but have a curved surface portion 4b at a part of them. The clutch gear 4 has a flange 4a along its entire outer circumference.

The control wheel 21, as described in connection with Fig. 7B, is provided with the start teeth 21b1, as well as with two different drive teeth 21b2 and 21b3. The teeth 21b1, 21b2 and 21b3 are formed at different portions of the wheel 21 in its width direction.

Figs. 12A, 12B and 12C and Figs. 13A and 13B show different states of engagement between the clutch gear 4 and the control gear 21. Figs. 12A and 12B show the states assumed during the normal recording operation. In the state of Fig. 13A, however, the guide pin 7 is not in this position. Above the ink receiver 23, the blade 17 and the ink carrier 19 are arranged, although this is not shown in this figure.

At this time, the clutch gear 4 rotates along with the rotation of the lead screw 2. However, since the starting tooth 4c1 and the starting tooth 21b1 are located outside a positional relationship that allows engagement (Fig. 13A), the control gear 21 does not rotate. In addition, since the drive teeth 21b2 at the left end of the control gear 21 and the flange 21h are in the positions where engagement (interaction) is possible with a small gap from the flange 4a, the control gear 21 is prevented from rotating in either direction.

Therefore, the control wheel 21 does not rotate inadvertently even if an erroneous manual force is applied or if an unexpected torque is applied to the control wheel 21. Therefore, the operating position of the recovery system is prevented from changing.

When the recording head 9 is moved to the home position to such an extent that the carrier 6 presses the clutch gear 4, the positional relationship between the clutch gear 4 and the control gear 21 finally becomes as shown in Fig. 13B. During the process, the positional relationship enabling engagement is established between the start tooth 4c1 and the start tooth 21b1 (at this time, however, the guide pin 7 is not yet in this position).

Then, with the movement of the guide pin 7 of the carriage 6 from the groove 3c to the groove 3b of the guide screw 2 (Fig. 2), the clutch wheel 4 rotates in the clockwise direction in Fig. 12A, whereby the positional relationship changes from the state shown in Fig. 12A to the state shown in Fig. 12C. Until the start tooth 4c1 is engaged with the start tooth 21b1, the control gear 21 does not inadvertently move to engage the other teeth first because the curved surface portion 4b (non-engagement portion) shown in Fig. 11 is closest to the control gear 21.

Therefore, the engagement between the clutch wheel 4 and the control wheel 21 always begins through the engagement between their start teeth, so that the rotation of the control wheel 21 always starts from the correct position.

This ensures the correct operation of the recovery system driven by the control wheel 21.

An additional advantage is that the positioning accuracy during assembly of the clutch wheel 4 and the control wheel 21 does not have to be very high.

The drive tooth 21b3 of the control gear 21, which is arranged in a different position as shown in Fig. 7B, is engaged when the curved surface portion 4b is again connected to the control gear 21. If the drive teeth are in the same position as the drive teeth 21b2, they come into contact with the curved portion 4b. Therefore, the drive teeth in the different position are engaged with each other.

As long as the control wheel 21 is rotated by the engagement of the drive teeth, the hook 6c of the carrier 6 slides on the surface of the control wheel 21 which is opposite to the recording area.

By doing this, the recording head 9 is prevented from deviating from the home position (which could occur if the guide pin 7 is removed from the groove 3b before, for example, the engagement between the predetermined teeth takes place). This is because the guide screw 2 is in contact with the recording head 9 in the starting position so that the guide pin 7 can move to the groove 3c.

In the previous embodiment, the series of recovery operations is carried out by two turns of the guide screw, but this is not limitative and the degree of rotation can be appropriately selected by the person skilled in the art. Therefore, the width can be increased when designing the clutch mechanism or the like.

Referring to Figs. 14A, 14B, 14C, 14D, 15A, 15B, 15C, 16A and 16B, and also referring to Figs. 12A, 12B, 12C, 13A and 13B, the operation will now be described. Figs. 14A, 14B, 14C and 14D show the various operating states of the mechanism containing the blade 17 or the like; Figs. 15A, 15B and 15C show the sequential operating states of the mechanism containing the cap 35; and Figs. 16A and 16B show the operation of a mechanism for introducing the residual ink into a residual ink container 37 within the roller 36.

First, the carrier 6 moves to the home position in the direction indicated by an arrow B. At this time, as shown in Fig. 13A, the guide pin 7 is engaged with the guide groove 2a, and the discharge outlets 9c of the head member 9a are in a position opposing to the ink carrier 19 (Fig. 14A). In this position, all the energy generating elements of the head member 9a for generating the energy to help discharge the ink are driven to discharge the ink therethrough (pre-discharge), thereby discharging the ink having a slightly increased viscosity or the like. Then, the recovery operation using the pre-discharge is terminated. Furthermore, pre-discharge may be periodically performed in this position to prevent the viscosity of the ink from increasing near the discharge outlets which are not used in the normal recording operation. Fig. 14A is a side view in this position.

As shown in Fig. 13B, when the rotation of the lead screw 2 moves the carrier 6 in the direction B, the clutch gear 4 is pushed by the pressing portion 6a so that the clutch gear 4 is moved in the same direction (B) to shift the start tooth 4c1 to a position for engaging with the start tooth 21b1 of the control gear 21. Thereafter, the clutch gear 4 rotates in synchronism with the lead screw 2, thereby engaging the start teeth with each other so that the control gear 21 rotates in the direction D as shown in Fig. 14B. On the other hand, the guide pin in the positioning groove 3b is guided by the insertion groove 3c, and therefore the carrier does not move even if the guide screw 2 rotates.

When the control wheel 21 rotates in the direction D, the adjustment lever 20 starts to rotate in a direction E since the gear of the control wheel 21 meshes with the gear of the adjustment lever 20. Up to this time, the blade lever 16 has not been moved since the hook 16c of the blade lever 16 is engaged with a pawl of the base frame 1, and only the adjustment lever 20 rotates. Sooner or later, the adjustment surface 20f of the adjustment lever 20 rotates in a direction F while pushing the rotary member 18a of the blade axis 18 downward, and therefore the blade 17 rotates in a direction G to be brought into a state of engaging with the surface on the discharge side.

When the control wheel 21 further rotates in the direction D, the hook 16c of the blade lever 16 is released from the pawl of the base frame 1, and the setting lever 20 and the blade lever 16 also continue to rotate. As shown in Fig. 14C, the blade 17 wipes the surface on the ejection side of the recording head element 9a. The excess ink or the like removed from the blade 17 is directed in only one direction, that is, downward in this embodiment. The ink liquid or the like thus removed is received or retained on the upper portion of the ink carrier 19. At this time, the ink carrier 19 is started to move the ink receiver 23. When the adjusting lever 20 further rotates, the ink carrier 19 and the sheet 17 slide on the surface of the cleaner 13a of the ink absorber 23, whereby the ink absorbed by the ink carrier 19 during the pre-ejection, the foreign matter removed from the sheet 17 from the surface on the ejection outlet side, or the like can be absorbed by the cleaner 23a, and in addition, the droplets of the ink deposited on the surface on the ejection side can be absorbed. Accordingly, the ink absorbing force of the ink carrier 19 can be maintained over a long period of time.

The control wheel 21 continues to rotate in the direction D. However, since the stop teeth 20a and 20b of the adjustment lever 20 oppose and contact the stop cam 21a of the control wheel 21, the rotation of the adjustment lever 20 is stopped, and at the same time, the portion without drive teeth of the control wheel 21 is presented, and therefore no rotary drive is exerted.

As described, the receiver for retaining the ink or the like removed from the sheet also serves as an ink receiver for pre-discharge, thereby the size of the apparatus can be reduced, and further the time required for the recovery operation can be reduced.

The control wheel 21 continues to rotate. Since the capping cam 21c of the control wheel 21 controls the rotation axis 32a of the capping lever 32c shown in Fig. 8, the capping lever 35 is at rest in the initial state at a position away from the ejection-side surface of the head member 9a as shown in Fig. 15A. When the control wheel 21 continues to rotate in the direction D, the capping cam 21c is released so that, as shown in Fig. 15B, the rotation lever 24f of the cylinder 24 is urged by the spring 22b of the ink receiving spring 22. This rotates the cylinder 24 in the direction F. Then, the capping portion 35a of the cap 35 is brought into pressure contact with the ejection-side surface, thereby effecting the capping operation. As this As will be understood, the capping portion 35a is brought into contact with the ejection-side surface gradually from the lower portion. By doing so, the air in the space between the capping portion 35a and the ejection-side surface can be ejected without repelling the meniscus of the ink in the ink ejection pipes of the recording head. Fig. 13B is a top view in this state. As will be understood, the pressing force of the cap brings the sealing surface 32d into tight contact with the cap sealing portion 35d.

The above is the cleaning and capping operation for the surface on the ejection side. Normally, the operation stops here, and in response to the subsequent generation of the recording signal, the reverse operation is performed, and then the recording operation is started.

A description will now be given of a suction recovery procedure which is carried out when good discharge is not achieved even by the pre-discharge.

When this is started, the control wheel 21 is further rotated from the capping position, whereby the cap lever 32 is pushed by the capping cam 21c to slightly displace the cap 35 away from the surface on the ejection side, as shown in Fig. 15C.

When the control wheel 21 further rotates in the direction D, it is again released from the cap cam 21c so that the cap portion 35a is in pressure contact with the surface on the ejection side.

The pumping action will now be described. When the recovery process is started after the capping process is completed, the suction process is started.

The rotation of the control wheel 21 causes the piston adjusting cam 21f to push the piston pressing roller 29 mounted on the piston rod 27, whereby the piston rod 27 moves in a direction H as shown in Fig. 16A. The piston 28 is pressed by the piston limiting collar 27b and is moved in the direction H. Then the groove 27f is closed so that a degree of vacuum is established in the pump chamber 42. Since a skin layer is provided on the outer periphery of the piston 28 and on the contact surface with the piston restricting collar 27b, the ink is prevented from leaking through the through pores of the foam material.

Since the ink line 24e of the cylinder 24 is closed by the piston 28, the piston 28 is only movable to increase the vacuum in the pump chamber 42. On the other hand, after the re-capping operation described above, the ink line 24e is opened as shown in Fig. 16A so that the ink from the head 9 is sucked in through the suction opening 35b of the cap 35. The sucked ink flows through the ink line 32f formed inside the cap lever 32, the connecting hole 33a of the lever seal 33 and through the ink line 24e of the cylinder 24 into the pump chamber 42.

With the continued rotation of the control wheel 21, the cap 35 is again moved slightly away from the surface on the ejection side of the recording head by the capping cam 21h, whereupon the ink is sucked from the surface on the ejection side and from the inside of the cap 35 by the vacuum remaining in the pump chamber 42 to remove the remaining ink from these portions.

Then, the control wheel 21 is rotated in the reverse direction (opposite to the direction shown by the arrow in Fig. 14D), the piston return cam 21i pulls the piston return roller 30, whereby, as shown in Fig. 16B, the piston rod 27 is moved in a direction indicated by an arrow J. When this occurs, since the piston 28 moves only after being contacted by the piston receiving portion 27c of the piston rod 27, a gap Δl is provided between the end face 28b of the piston 28 and the piston limit collar 27b. Then, by the movement of the piston rod 27 and the piston 28, the excess ink accommodated in the pump chamber 42 is discharged to the vicinity of a center of the remaining ink accommodating portion 27c of the piston rod 27. material 37 is ejected through the above-described gap Δl, the groove 27f of the piston rod 27, the ink pipe 24c of the cylinder 24 and the ink pipe 24h of the residual ink pipe 24g. At this time, the ink pipe 24e of the cylinder 24 is closed by the piston 28 in the initial state of the operation of the piston 28, and therefore the residual ink does not flow in the reverse direction to the cap 35.

Fig. 17 shows in summary the sequential operations for pre-discharge and suction recovery. However, the illustrated procedure is for the case where the blade 17 is expected to be in the ready state (set state shown in Fig. 14B); the blade 17 is inclined with respect to the receiver 23 after the wiping operation (reset state shown in Fig. 14A); and thereafter the blade 17 is set in a ready state immediately before the setting lever 20 returns to its original position.

Referring now to Figs. 3A and 3B, a description will be given regarding the recording medium conveying mechanism from the recording operation to the sheet discharging operation.

In these figures, the sheet enclosing plate 38 is made of a fluorinated resin or a material to which carbon fibers are mixed. It presses the fed recording sheet or paper to maintain a predetermined gap between the recording sheet and the surface on the ejection side of the recording head 9. The holding force of the sheet enclosing plates 38 is provided by the spring 38D. Figs. 18A and 18B show details of the mechanism.

In Fig. 18A, the sheet-containment plates 38 exert the holding force on the sheet-conveying roller. The axle 38A has a "D" shape (part of its circumference is cut away so that a straight surface is formed), and it is in sliding relation with the sheet-containment plates 38 in the rotational direction. In the state of this figure, the straight portion of the axle 38A is in such a position that it engages the end 38F of the spring plate 38D. Therefore, the end 38F of the plate 38 is pushed upward by the spring plate 38D. Accordingly, the containment plate 38 is caused to rotate in the clockwise direction about a rotation axis of the shaft 38A to exert the holding force on the sheet conveying roller 36.

On the other hand, Fig. 18B shows the state in which the pressing force is released by the blade confining plate 38. When the shaft 38A rotates so that the arcuate portion of the shaft 38A presses the end 38F, the spring plate 38D is completely pressed down, and therefore the end 38E is not pressed by the spring plate 38D.

In this released state, the shaft 38A and the sheet enclosing plate 38 are engaged with each other with a certain amount of friction, so that the sheet enclosing plate 38 is prevented from changing its rotational position to a large extent. Therefore, even if the need arises to release the pressing force by the sheet enclosing plate 38, the movement of the recording head or the like is not restricted by the sheet enclosing plate 38.

The sheet confining mechanism described above is adapted to provide such a pressing force that does not prevent proper conveyance of the recording sheet by the sheet conveyance roller 36 within a limited space.

In particular, the leaf confinement plates themselves are not made of an elastic material, and the compression force is provided by leaf springs arranged on the lower base frame 1, which is normally an empty space, and therefore the width of adjustability for the compression force achieved by adjusting the lengths of the leaf springs is increased. In addition, the size of the leaf confinement members can be reduced.

The leaf spring 38D is attached to the base frame 1 by a fastening member not shown.

Referring again to Figs. 3A and 3B, a sheet ejection roller serves to eject the recording sheet subjected to the recording process. Spur wheels 61 serve to hold the recording sheet which has been fed by the ejection roller 60, to restrict the sheet ejection direction of the recording sheet, and to ensure the feeding force thereon.

A transfer roller 62 is arranged between the sheet discharge roller 60 and the sheet transfer roller 36 to transfer the rotation of the sheet discharge roller 36 to the sheet discharge roller 60. The transfer of rotation is effected by the frictional force provided by the contact between them. The sheet discharge roller 60 is generally cylindrical, but the diameter at its opposite end portions is different from that at the middle portion. The transfer roller 62 contacts the middle portion of the discharge roller 60, which has a smaller diameter. Therefore, the opposite end portions having the larger diameter and serving to feed the recording sheet rotate at a larger peripheral speed than the sheet feed roller 36. Therefore, when the sheet is ejected, the recording sheet is slightly stretched so that the recording surface can be maintained in a good condition.

The rotation axes of the transmission roller 62 and the tail wheels 61 are made of coil springs having an appropriate elasticity coefficient. The mechanism will now be described in detail, taking the tail wheel 61 as an example, by referring to Fig. 19.

In Fig. 19, an axle 61A is made of a coil spring which extends through the center of the tail wheels 61 on their opposite sides and is rotatably engaged with the tail wheels 61. Bearings 103B support the opposite ends of the shaft 61A and are formed as a part of the inner cover 103 shown in Fig. 1. The bearings 103B support the axle 61A for sliding movement in the longitudinal direction. Limiting members 103C limit the movement of the tail wheel 61 in the direction of the rotation axis and in the direction perpendicular thereto. They are provided at opposite ends of the shaft 61A. sides of the tail wheel 61 and are formed as a part of the inner cover 103.

By the construction described above, the axle 61A supports the tail wheel 61, and at the same time it provides a pressing force on the tail wheels 61 toward the ejection rollers 60 by its spring force.

The inner cover 103 has a spring 103A formed at its rear end as shown in Fig. 3A to receive a pressing force to the sheet ejection roller 60 by the reaction force from the housing 101. By the cooperation between the pressing force and the spring force of the rotation shaft 61A, the spur gears 61 provide an appropriate pressing force to the sheet ejection rollers 60.

Since the inner cover 103 receives the pressing force, the engagement between the fastening member 103D of the inner cover 103 and the rotation axis 60C of the ejection rollers 60 is ensured as shown in Fig. 3A. As a result, the positional relationships between the spur wheels 61 and the ejection roller 60 are kept constant at all times. Alternatively, by abutting and fixing the rotation axis 60C to a locking member or the like, the highly accurate relationship can be maintained, regardless of the accuracy of the inner cover.

The function of the rotary shaft 62A, which is made of a coil spring, is the same as that of the transfer roller 62. In particular, the contact pressure of the sheet feed roller 36 and the sheet discharge roller 60 is provided by the spring force of the shaft 62A.

As described above, the ejection roller 60 has a smaller diameter in the middle portion in the longitudinal direction than in the opposing portions. This will be described in detail in connection with Fig. 20.

In Fig. 20, a cover member 60A is made of a rubber material. A core member 60D is cylindrical, but the diameter at the opposite ends is larger than that at the center. The sheet ejection roller 60 is manufactured by covering the core member 60D with a cylindrical cover member 60A.

Therefore, it is not necessary to mold rubber material or the like integrally into the mold, and therefore the sheet ejection roller can be manufactured relatively easily and at a low cost.

A groove 60B (Fig. 3A) formed throughout an end portion of the sheet conveying roller 60 serves to lock an end portion of the recording sheet when the recording sheet is ejected by the ejecting roller 60, so that the sheet ejection operation is ensured even if the position of the recording sheet deviates.

The construction of the core member 60D is not limited to that described above. For example, it may be an extension of the grooves 60B having a smaller central portion if it is formed as a cylinder by covering it with the rubber material.

Referring now to Figs. 21 and 22, the description will be given for the case where the ink-jet recording apparatus of this embodiment is arranged and operated vertically.

If the apparatus is arranged vertically, then it can be used with an automatic cut sheet conveyor 200, or it can be used with a thick material such as an envelope, which is provided through a feed inlet at the rear of the apparatus.

When the normal recording sheets usable with the automatic conveyor are used, the upper cover 102 can be used as a stacking basket for the recording sheets. In this case, the upper cover 102 is fixed at an angle different from the angle when the upper cover 102 is used as a sheet guide for feeding sheets.

The use of the top cover 102 as a stacker will now be considered.

The upper cover 102 is located in such a manner that the ejected recording sheet is to some extent in the air due to its rigidity and first contacts the top cover 102 or the tip of the stacked sheets near an upper end 102A of the top cover 102. By doing so, the sheet being discharged slides on the uppermost of the already stacked sheets only within a limited range, that is, in the vicinity of the leading edge of the recording sheet. This minimizes the sliding movement of the recording sheet, so that the contamination of the recording sheet by insufficiently fixed ink can be prevented.

To achieve this, the upper end portion 102A is located near the sheet ejection line adjacent to the common tangent between the sheet conveying roller 36 and the sheet ejection roller 60, and in addition, the lower end portion 102B is lower than the upper end portion 102A.

In addition, the arrangement is such that when the trailing end of the recording sheet stopped on the upper end portion 102A is completely ejected, the sheet falls down in position without sliding on the stack.

To achieve this, the length of the top cover 102 when measured in the sheet ejection direction, i.e., the length from the upper end 102A to the lower end 102B, is important. If the recording sheet is a common sheet, and if the sheet is ejected substantially horizontally, then the length is 60 - 90%, preferably 70 - 80% of the length of the recording sheet.

If the construction of the recording device is different, if the conditions of use are different, or if the sheet ejection direction is different, the length of the stacking basket is determined by the person skilled in the art in consideration of the above.

In Fig. 21 and 22, reference numeral 108 denotes a tongue to prevent the stacked Recording sheet is inserted into the sheet feed inlet 106.

Referring to Figs. 23 - 28, the recording head 9 and the carrier 6 will now be described in detail.

Fig. 23 is an axonometric view showing the external appearance of the recording head 9 which comprises as a unit an ejection element 9a and an ink tank 9b. A pawl 906e is engaged with a hook of a carrier when the recording head 9 is mounted on the carrier 6. As will be understood from this figure, the pawl is within an entire length, i.e., within the length measured without the pawl 906e. Adjacent to the ejection element 9a at the front of the recording head 9, a stopper positioning portion is provided, although it is not shown in this figure. An opening 906f is formed in the head to receive a support plate which projects from the carrier 6 to support a flexible pad and a rubber plate.

24A and 24B are an exploded axonometric view and an axonometric view of the external appearance of the ink jet recording head shown in Fig. 23. As described previously, it is a disposable type recording head having an integral ink container (ink supply source).

In Fig. 24A, reference numeral 110 denotes a heater board comprising a Si substrate, electrothermal converting elements (ejection heaters) and aluminum wires or the like for supplying electric energy, the converting elements and the wires being formed by a thin film method. The heater board 110 is electrically connected to a circuit board 210, and the respective wires are connected to each other by wire connections.

The recording head is provided with a top plate 400 having partition walls to define ink lines and an ink chamber. In this embodiment, the top plate 400 is made of a resin material which has a one-piece opening plate.

A support member 300 made of metal and a retaining spring 500 are engaged with each other with the heater board 110 and the upper plate 400 therebetween, so that the heater board 110 and the upper plate 400 are clamped together by the pressing force applied by the retaining spring 500. The support member 300 may have the circuit board 210 adhered to it, and the support member 300 may have a positioning stopper with respect to the carrier 6. The support member 300 also serves as a member for radiating the heat from the heater board 100 resulting from the driving of the electrothermal transducers. An ink supply chamber 600 receives ink from the ink tank 9b (ink supply source) and serves as a sub-tank for supplying ink into the common chamber formed by adhering the upper plate 400 to the heater board 110. A filter 700 is disposed in the supply chamber 600 near the ink supply port to the common chamber. The supply chamber 600 is covered by a cover 800.

The ink container 9b contains an ink absorbing material 900. An ink supply port 1200 supplies ink to the ejection unit 9a having the various parts 110 - 800. Before the ejection unit 9a is attached to the portion 1010 of the ink container 9b, the ink is injected through the supply port 1200, whereby the ink is absorbed by the absorbing material 900.

The cartridge has a cover 1100 provided with a hole 1301 to establish communication between the interior of the cartridge and the environment. A water-repellent material is provided in the hole 1301, thereby preventing the ink from leaking out through the hole 1301.

When the ink is supplied into the ink tank 9b through the supply opening 1200, the ejection unit 9a, which has various elements 110 - 800, is positioned with respect to the section 1010. The correct positioning between them is performed through projections 1012 of the ink container 9b and corresponding openings 312 formed in the support member 300. Therefore, the recording head 9 is manufactured in the form of a cartridge as shown in Fig. 24b.

The ink is supplied to the supply chamber 900 from the inside of the cartridge through the supply port 1200, a hole 320 of the supply member 300 and an inlet port of the supply tank 600 at the rear in Fig. 24A. From the supply chamber 600, the ink is supplied into the common chamber through a supply pipe and an ink inlet 420 of the upper plate 400. In the connecting portions of the ink supply pipe, a suitable gasket made of silicone rubber or butyl rubber or the like is attached for sealing to ensure the ink supply.

Figs. 25A, 25B and 25C are a top view, a left side view and a right side view of the carrier 6.

A support plate 606 projects from the underside of the carrier 6. It supports a flexible base 604 and a rubber pad 605 having projections 605A corresponding to contact pads formed on the base 604.

A stopper member 607 projects from the underside of the carrier 6 in the region of its front end. The thickness of the stopper member 607 is desirably as small as possible to ensure the maximum volume for the ink container within the limited space on the carrier 6. Therefore, the member 607 has three ribs 608 to provide its mechanical strength. The ribs 608 extend in a direction of movement of the carrier 6 to provide strength against the direction of rotation due to attachment or detachment of the recording head with respect to the carrier 6. In addition, the ribs 608 have a dimension such that they project approximately 0.1 mm beyond this surface on the ejection side when the recording head 9 is attached. By doing this, the recording sheet is prevented from falling on the surface the ejection side, and therefore damage to the surface on the ejection side is prevented even if the recording sheet is present in the moving path of the recording head for one reason or another.

A contact lever 602 is operated when the recording head is to be mounted on or removed from the carrier 6. It is rotatably mounted on an axis 601d on the carrier 6. A contact hook 603 is partially contactable with the recording head 9 for mounting and demounting the recording head 9 by operating it into engagement with a portion of the contact lever 602. The hook 603 has an elongated slot 603c which is guided by a guide pin 601c mounted on the carrier 6 during the mounting and removal operations.

The attachment and removal mechanism comprising the contact lever 602, the contact hook 603 or the like is arranged on one side of the carrier 6, i.e., on one side in the moving direction of the carrier 6, and therefore the mechanism does not require a large dead space to allow movement of the carrier.

A description will now be given of the stopper sections for the positioning of the recording head. The stopper sections 601a are effective for positioning in the left-right direction, and two of them are on one side of the stopper member 607. As for positioning in the left-right direction, a stopper section 601f on the support plate 606 is used in addition to the stopper sections 601a.

A stopper portion 601b is formed on a side and on a lower portion of the stopper member 607 to position the recording head in a front-rear direction.

The stopper portions 601c are for positioning in the vertical direction, and two of them are formed on a side and bottom of the stopper member 607, and on a lateral lower portion of the support plate 606, respectively.

Figs. 26A and 26B are a top view and a side view when the recording head 9 is mounted on the carrier 6.

A stopper portion 906a is formed on the recording head 9 for stopping the carrier 6, and the stopper portions 906b and 906c correspond to the stopper portions 601b and 601c, respectively.

Referring now to Fig. 26A, the operations in the various sections when the recording head is mounted on the carrier will now be described.

The stopper portion 906a of the recording head 9 abuts against the stopper portion 601a of the carrier 6, and at the same time, the pawl 906e of the recording head 9 is pushed to the left in this figure by the urging force of the coil spring 607a through the hook 603 engaged therewith. Therefore, the recording head 9 receives a moment about the stopper portion. At this time, the pad 906d of the recording head is brought into abutment against the stopper portion 601f, whereby the recording head 9 is correctly positioned in the left-right direction, and this position is maintained.

Furthermore, at this time, the projections 605A of the rubber pad 605 are compressed and deformed by abutting against the base 906d. Due to the deformation, a pressure-contact force is generated between the contact pads of the flexible pads 604 and the contact points of the plate 906d. In this case, since the base 906d comes into contact with the stopper portions 601f, the amount of deformation of the projections 605A is constant, so that the pressure-contact force is stable.

In the figure, the compressed and deformed state of the projections 605A is not shown.

As will be described below, the positioning of the recording head 9 in the front-back direction and in the vertical direction has already been achieved by the assembly process.

Fig. 27 is a top view of the carrier 6 before the recording head has been attached, the contact lever 602 being omitted in this figure for the sake of simplicity.

In the state shown in this figure, the contact lever 602 is retracted (backward) (Fig. 25B), and at this time the position of the contact hook is as shown in Fig. 27. The carrier waits for the recording head 9 to be fixed in this position.

28A, 28B and 28C are top views showing the process in which the recording head is assembled. The recording head 9 is moved to the vicinity of the carrier 6 from the direction above the carrier 6 so that the opening 906f receives the support plate 606. At this time, as shown in Fig. 28A, the recording head 9 is mounted on the carrier 6 with an inclination due to the positional relationship between the stopper member 607, the support plate 606 and the contact hook 603 and due to the relationship between the total length of the recording head 9 and the opening 906f.

When the contact lever 602 is rotated in the counterclockwise direction (Fig. 25B), the contact hook 603 rotates in the counterclockwise direction about the axis 601e and then, when it becomes horizontal, it moves to the left in the state shown in Fig. 28B.

In conjunction with this movement of the contact hook 603, the recording head 9 is pushed to the upper left part in this figure by engaging with the contact hook 603. Then, the stopper portion 906a of the recording head slides to abut against the stopper portion 601a, and the stopper portion 906b abuts against the stopper portion 601b. In this state, the base 906d and the flexible base 604 do not contact each other.

With the further rotation of the contact lever 602 in the clockwise direction, the contact hook 603 is moved further to the left. Meanwhile, it moves the pawl 906c, and therefore the recording head 9 rotates in the clockwise direction, around the stopper between the stopper portions 906a and 906b in the state shown in Fig. 28C, thereby determining the position of the recording head 9 on the carrier 6.

The front-back and vertical positions are determined during the assembly process.

In the state shown in Fig. 28C, the contact lever 602 is pressed leftward by the coil spring 607a into the interior of the rotation axis as described above, and the pressing force acts to fix the recording head 9 on the carrier 6 through the contact hook 603.

As will be understood from the above, the mounting of the recording head in this embodiment involves a translational movement and a rotational movement of the recording head, and the angle of rotation is about 5 degrees.

Since the recording head is mounted with a small angle of rotation, no special space is required for mounting the recording head.

Referring to Figs. 25A and 26A, the relationship between the contact lever and the contact hook will be described.

As shown in these figures, the contact lever 602 is provided with two flat surfaces 602a and 602b and a single inclined surface (cam surface) 602c. When the recording head 9 is mounted (Fig. 28C), the surface 602a engages a portion 603a of the contact hook 603 to apply a pressing force to the hook 603.

The relationship between the lever 602 and the hook 603 during the process of dismounting the recording head will now be described. The contact lever 602 is rotated from the state shown in Fig. 26A in a direction opposite to that of the mounting process, with the cam surface 602c of the contact lever rotating in contact with the cam surface 603b of the contact hook. Then, the contact hook 603 moves to the right until the left end of the elongated slot 603c on the shaft 601e of the carrier 6 Then, it rotates in the clockwise direction about the axis 601e. When the stop surface of the contact lever 602 contacts the flat surface 602b, it abuts against one end of the cam surface 603b of the contact hook 603, so that the state shown in Fig. 25A is achieved.

In the process from the state of Fig. 26A to the state of Fig. 25A, the recording head 9 is ejected by the portion 603d of the contact hook.

The present invention is particularly suitable for use with a bubble jet recording head and a bubble jet recording apparatus as proposed by Canon Kabushiki Kaisha, Japan.

In particular, the recording head and device are of the type disclosed in U.S. Patent Nos. 4,723,129 and 4,740,796, which disclose a typical construction and operating principle. The construction and principle are applicable to a so-called on-demand type recording system and a so-called continuous type recording system. In particular, however, the bubble jet construction and principle are suitable for the on-demand type because the principle is, in brief, that at least one drive signal is applied to an electrothermal transducer disposed in a liquid (ink) retaining sheet or path, the drive signal being sufficient to provide such a rapid temperature rise above a core boiling initiation point as to provide thermal energy to generate film boiling at the heating portion of the recording head, whereby a bubble can be formed in response to the drive signal. By the development and contraction of the bubble, the liquid is ejected through an ejection outlet to produce at least one droplet. The driving signal is preferably in the form of a pulse because the development and contraction of the bubble can be instantaneous and therefore the liquid is ejected at a rapid The drive signal in the form of a pulse is preferably as disclosed in U.S. Patent Nos. 4,463,359 and 4,345,262. In addition, the temperature rise rate of the heating surface is preferably as disclosed in U.S. Patent No. 4,313,124.

The structure of the recording head may comprise the combination of the ejection outlet of the liquid pipe and the electrothermal transducer as disclosed in the above-mentioned U.S. patents (linear liquid pipe or rectangular liquid pipe), or it may be that disclosed in U.S. Patent Nos. 4,558,333 and 4,459,600 in which the heating portion is arranged in a bent portion. The present invention is also applicable to the structure disclosed in Japanese Patent Laid-Open No. 123670/1984 in which a common slit is used as the discharge outlets for a plurality of electrothermal transducers, and also to the structure disclosed in Japanese Patent Laid-Open No. 138/1984 in which an opening for receiving pressure waves of thermal energy is formed corresponding to the discharge portion.

The present invention is effectively applicable to a so-called full-line type recording head having a length covering the maximum recording width. Such a recording head may comprise a single long recording head or a plurality of recording heads combined to cover the entire width.

The present invention is also effectively applicable to a recording head in the form of a replaceable chip which is electrically connected and supplied with ink from the main assembly of the recording device when it is installed in the main assembly, or in the form of a cartridge type recording head which is integrally mounted.

The provision of the recovery means or the auxiliary means for the pre-ejection process is preferable, since it can further stabilize the advantageous effects of the present invention. As for examples of such means, there are capping means for capping the recording head, cleaning means for cleaning the recording head, pressure applying means or suction means for applying pressure or sucking liquid in the line, pre-heating means using the ejection electrothermal transducers or a combination of the ejection thermal transducers and additional heating means, and means for performing pre-ejection of the liquid not for the recording operation. These can stabilize the recording operation.

As for the recording mode of the recording device, it is not limited to recording only by a main color such as black. The present invention is effectively applicable to a recording device having an integral recording head or a combination of a plurality of recording heads for recording in at least one of the following modes, namely, the multi-color mode using different colors and a full-color mode using color mixtures.

In the above embodiment, the ink has been described as a liquid. However, the ink may be a material which is solid at room temperature or an ink material which softens at room temperature. Since the ink in the ink jet recording system is usually controlled within the temperature which is not lower than 30°C and not higher than 70°C in order to stabilize the viscosity of the ink in order to stabilize the ejection, the ink may be such that it is liquid when the recording signal is applied during use. The present invention is applicable to the ink which is liquefied by the application of the thermal energy thereto. In an example of such a type, the thermal energy is surely consumed for the phase transition from the solid state to the liquid state so as to suppress the temperature rise by the thermal energy. In another example, the ink is solidified, when left as it is, for the purpose of preventing evaporation. In these examples, the ink is liquefied by the application of thermal energy thereto in response to the recording signal, and the liquefied ink is ejected. In one example, the ink begins to be solidified as soon as it reaches the recording medium. Thus, an ink material may be held as a liquid or as a solid ink in holes or recesses held in a porous sheet, as disclosed in Japanese Patent Application Laid-Open Nos. 56847/1989 and 7126/1985. In this case, the ink faces the electrothermal transducers.

The most effective way to actuate the ink described above is to cause it to film boil.

Claims (8)

1. Ink jet recording apparatus using a recording means (6, 9) to deposit ink on a recording medium (40) arranged in a recording area, the ink jet recording apparatus comprising a recovery means (15 - 35) for contacting an ink ejection side surface (9a) of the recording means (6, 9) to clean or cover it, the recording means (6, 9) being movable with respect to the recording medium (40) to effect recording on the latter within a recording area, as well as being movable to the outside of the recording area to face the recovery means (15 - 35), characterized by an axis (51) which is connected to a portion of the recording means (6, 9) and which is rotatable about an eccentric axis to change the positional relationship between the recording means (6, 9) and the recording medium (40), the axis (51) having an eccentric portion to change the change of a gap between the recording means (6, 9) and the recording medium (40) in the recording area, and an axis (51a) to maintain a predetermined positional relationship between the recording means (6, 9) and the recovery means (15 - 35) outside the recording area, regardless of the gap between the recording means (6, 9) and the recording medium (40) in the recording area. 2. Device according to claim 1, characterized by a drive means (2 - 5, 7, 8, 11 - 13) for moving the recording means (6, 9) in a direction which is different from the direction in which the recording medium (40) is conveyed, the axis (51) being suitable for guiding the recording means (6, 9) when it is moved by the drive means (2 - 5, 7, 8, 11 - 13). 3. Device according to claim 2, characterized in that the drive means (2 - 5, 7, 8, 11 - 13) comprises a guide screw (2, 2a). 4. Device according to one of the preceding claims, characterized in that the recording means (6 - 9) comprises an electrothermal transducer for generating energy by which the ink is ejected from the recording means (6 - 9). 5. Ink jet recording apparatus comprising a carriage (6) for carrying a recording means (9) for depositing ink on a recording medium (40), an axle (2) for guiding the carriage (6), and a recovery means (15 - 35) for cleaning an ink ejection side surface (9a) of the recording means (9) or covering it, the carriage (6) being movable in a direction different from the direction in which the recording medium (40) is conveyed, characterized by a moving means (1h, 1k, 11, 50, 50a - 50e) for moving the axle (2) and the recovery means (15 - 35) in a direction to form a gap between the recording means (9) and the recording medium (40). whereby the positional relationship between the recovery means (15 - 35) and the recording means (9) is kept constant, independently of the positional relationship between the latter and the recording medium (40). 6. Device according to claim 5, characterized in that the movement means (1h, 1k, 11, 50, 50a - 50e) comprises a first Movement member (50b) for moving a plate-like support member (50) on which the recovery means (15 - 35) is mounted, and a second movement member (50a) for moving the axis (2). 7. Device according to claim 5 or 6, characterized in that the recovery means (15 - 35) comprises a cover mechanism (35), a cleaning blade (17) and a drive source (11) therefor, the drive source (11) applying a rotational force to the shaft (2) via a transmission mechanism (12, 13), and the shaft (2) having a guide screw (2, 2a) for moving the carriage (6) by the rotation of the guide screw (2, 2a). 8. Device according to one of claims 5 to 7, characterized in that the recording means (9) comprises an electrothermal converter for generating heat, through which the ink is ejected from the recording means (9).