Image recording apparatus

A conveyor unit in an image recording apparatus can convey a record medium, being unwound from a roll, in either of a first direction in which the roll is unwound and a second direction reverse to the first direction. The image recording apparatus includes first and second contact mechanisms capable of bringing the record medium into close contact with a conveyor member at positions distant in the respective first and second directions from an image recording position where an image recording head records an image on the record medium. The first contact mechanism brings the record medium, being conveyed in the first direction, into close contact with the conveyor member. The second contact mechanism brings a part of the record medium, being conveyed in the second direction, into close contact with the conveyor member, which part was beyond the conveyor member in the first direction when the conveyance direction of the record medium by the conveyor member was switched from the first direction to the second direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image recording apparatus for recording an image on a record medium being unwound from a roll.

2. Description of Related Art

As an image recording apparatus, an inkjet printer is known that has inkjet heads in each of which a large number of nozzles are formed. In the inkjet printer, ink is ejected from the nozzles of each head onto a record medium being conveyed, to record a desired image on the record medium. As the record medium for the inkjet printer, a cut sheet of paper cut in advance into a predetermined length is generally used. However, attendant upon the extension of the range of use of printers, not only such cut sheets of paper but also long papers are used for printers.

In general, a long paper is wound into a roll, which is rotatably supported by a roll supporter in a printer, for example, as disclosed in JP-A-10-139239. A portion near the leading edge of the paper being unwound from the roll is pinched by a pair of pickup rollers. In this state, the rollers are rotated. Thereby, the paper being unwound from the roll is conveyed for heads. Hereinafter, the direction in which the paper being unwound from the roll is advanced will be referred to as forward, and the reverse direction will be referred to as backward.

The paper is put on a conveyor belt of a conveyor unit and conveyed by the conveyor belt. An image is recorded on the paper at the position opposite to the nozzles of the heads. Thereafter, the paper is cut by a cutter. The part of the paper being ahead of the cutting position by the cutter is thereby cut off into a separate cut sheet discontinuous from the roll, and thereafter discharged out of the printer. On the other hand, the part of the paper in the rear of the cutting position by the cutter, on which part no image has been recorded, can be used for image recording in the next printing operation. Therefore, the part of the paper is conveyed backward to be rewound onto the roll.

The paper being unwound from the roll is apt to curve due to its tendency to curl as an aftereffect of winding. In particular, the vicinity of the leading edge of the paper is apt to greatly curve because the leading edge is an unrestrained free end.

In an inkjet printer having a construction in which a paper is put on a conveyor belt to convey, the paper being conveyed can be in close contact with the conveyor belt by the adhesion of the conveyor belt or the like so that the paper can not separate from the conveyor belt. However, the vicinity of the leading edge of the paper immediately after being cut by a cutter, is at the position of the cutter, distant forward from the conveyor belt, where the vicinity of the leading edge of the paper has been peeled off the conveyor belt. Thus, the vicinity of the leading edge of the paper is apt to curve upward due to its tendency to curl. Under this condition, if the paper is rewound as described above, the curved portion of the paper may come into contact with a head and as a result, ink may adhere to the paper.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an image recording apparatus wherein a record medium can be prevented from coming into contact with any image recording head, in particular, when the record medium is conveyed in the reverse direction to the direction in which a roll is unwound.

According to an aspect of the present invention, an image recording apparatus comprises a roll supporter, a conveyor unit, an image recording heads an image recording controller, a first contact mechanisms and a second contact mechanism. The roll supporter rotatably supports a roll into which a long record medium has been wound. The conveyor unit comprises an adhesive conveyor member on which the record medium being unwound from the roll is put. The conveyor unit can convey the record medium put on the conveyor member in either of a first direction in which the roll is unwound and a second direction reverse to the first direction. The image recording head records an image on the record medium put on the conveyor member. The image recording controller controls the image recording head to record the image on the record medium being conveyed in the first direction. The first contact mechanism can bring the record medium into close contact with the conveyor member at a position distant in the second direction from an image recording position where the image recording head records the image on the record medium. The second contact mechanism can bring the record medium into close contact with the conveyor member at a position distant in the first direction from the image recording position. The first contact mechanism brings the record medium, being conveyed in the first direction, into close contact with the conveyor member. The second contact mechanism brings a part of the record medium, being conveyed in the second direction, into close contact with the conveyor member, which part was beyond the conveyor member in the first direction when the conveyance direction of the record medium by the conveyor member was switched from the first direction to the second direction.

According to the invention, when image recording is performed on the record medium being conveyed in the first direction, because the first contact mechanism brings the record medium into close contact with the conveyor member, good image recording can be achieved. On the other hand, when the record medium is conveyed in the second direction reverse to the first direction after image recording and, for example, being cut, the second contact mechanism can bring the portion of the record medium near its leading edge, which is apt to curve upward due to its tendency to curl, into close contact with the conveyor member. Thus, the record medium is prevented from coming into contact with the image recording head.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, a preferred embodiment of the present invention will be described with reference to drawings.

First, the whole construction of an inkjet printer according to the embodiment of the present invention will be described with reference toFIGS. 1 and 2. In the below description, the direction indicated by an arrow A inFIG. 1, in which a roll500is unwound, will be referred to as forward, and the reverse direction indicated by an arrow B will be referred to as backward.

As shown inFIG. 1, the printer10of this embodiment is a line printing type color inkjet printer having four inkjet heads12. The printer10includes a cassette20and a casing11. The cassette20receives therein a roll500of a long paper. The cassette20is in front of the casing11. They are fixed to each other with a not-shown fixing member in a state that a protrusion of the cassette20corresponding to a front portion of a paper feed port23is inserted into a paper feed unit14of the casing11.

The cassette20has a detachable case21. The case21is made up of an upper case21aand a lower case21bseparable from each other.

Within the lower case21b, a roll supporting mechanism22is disposed as one of a shock absorbing mechanism for absorbing a shock to the paper500a. The roll supporting mechanism22supports the roll500so that the roll500can be rotatable, elastically displaceable, and swingable. The roll supporting mechanism22includes three supporting rollers24a,24b, and24crotatably supporting the roll500, and two springs25attached to both ends of the supporting roller24cbeing at a lower right position inFIG. 1, thoughFIG. 1shows only one spring25.

Each of the supporting rollers24a,24b, and24cis cylindrical and has its axis of rotation parallel to the width of the printer10perpendicular to the direction A and perpendicular toFIG. 1. The supporting rollers24a,24b, and24care arranged at substantially regular intervals within a hollow of the roll500. Any of the supporting rollers24a,24b, and24cis detachable. Both ends of each of the supporting rollers24a,24b, and24care inserted in elongated holes formed in not-shown side walls of the lower case21bparallel toFIG. 1. Both ends of each of the supporting rollers24a,24b, and24care supported in the elongated holes so as to be slideable.

One end of each spring25is attached to the corresponding end of the supporting roller24cand the other end of each spring25is attached to the lower case21b. The springs25supports the supporting roller24cso that the supporting roller can be rotatable, elastically displaceable, and swingable. Particularly in this embodiment, the springs25are biasing the supporting roller24cin a direction at an obtuse angle with the direction in which the paper500ais unwound from the roll500.

A paper feed port23is formed in the upper case21afor sending out the paper500abeing unwound from the roll500, to the paper feed unit14of the casing11. Within the upper case21adisposed are a tensioner26as one of the shock absorbing mechanism for absorbing a shock to the paper500a, and a guide roller29for guiding the paper500ato the paper feed port23.

The tensioner26is disposed between the roll500and the paper feed port23. The tensioner26gives the paper500atension. The tensioner26includes a tension roller27and two springs28attached to both ends of the tension roller27, thoughFIG. 1shows only one spring28.

The tension roller27is cylindrical and has its axis of rotation parallel to the width of the painter10. The tension roller27is disposed so that its outer circumferential surface can come into contact with the back surface of the paper500a. The tension roller27is detachable. Both ends of the tension roller27are inserted in elongated holes formed in not-shown side walls of the upper case21aparallel toFIG. 1. Both ends of the tension roller27are supported in the elongated holes so as to be slideable.

One end of each spring28is attached to the corresponding end of the tension roller27and the other end of each spring28is attached to the upper case21a. The springs28supports the tension roller27so that the tension roller27can be rotatable, elastically displaceable, and swingable.

The guide roller29is cylindrical and has its axis of rotation parallel to the width of the printer10. The guide roller29is rotatably supported in the rear of the paper feed port23.

Next, components disposed within the casing11will be described. Within the casing11, there are disposed, in the order from the rear, a paper feed unit14, a first contact mechanism40, heads12, a conveyor unit30disposed to be opposed to the heads12, a second contact mechanism60, a curl correcting mechanism70, a cutting mechanism50, and a paper discharge unit18.

Upon printing, the paper500abeing unwound from the roll500is conveyed in the direction A for the heads12. The paper500ais put on a conveyor belt33of the conveyor unit30and conveyed by the conveyor belt33. An image is recorded on the paper500aat the position below the heads12. Thereafter, the paper500ais cut by the cutting mechanism50. The part of the paper being ahead of the cutting position is thereby cut off into a separate cut sheet500bdiscontinuous from the roll500, as shown inFIG. 5C, and thereafter discharged out of the printer10through the paper discharge unit18.

The paper feed unit14includes a paper feed roller15, a paper feed table16disposed80as to be along the back surface of the paper500a, and a not-shown guide wall substantially perpendicularly standing on the paper feed table16and extending in the direction A. The paper feed roller15can relatively press the paper500aonto the paper feed table16so that the paper500acan be held on the paper feed table16.

The paper feed roller15is cylindrical and disposed so that its outer circumferential surface can come into contact with the back surface of the paper500a. Both ends of the paper feed roller15are supported on not-shown side walls of the casing11parallel toFIG. 1. One end of the paper feed roller15is connected to a paper feed motor89shown inFIG. 3. The paper feed motor89drives the paper feed roller15to rotate. When the paper feed roller15is rotated in a state that the paper500ais in contact with the outer circumferential surface of the paper feed roller15, the paper500ais conveyed with being pressed onto and held on the paper feed table16.

In plane, the axis of rotation of the paper feed roller15is not parallel to the width of the paper500abut oblique at about three degrees. Therefore, the paper500abeing conveyed by the rotation of the paper feed roller15is brought near to the above-described not-shown guide wall. By thus bringing a aide of the paper500ainto contact with the guide wall, the paper500ais made parallel to the direction A. In this manner, oblique movement of the paper500ais corrected before printing.

Not-shown one-way clutches are provided on both ends of the paper feed roller15. The one-way clutches allow the paper feed roller15to be driven by the paper feed motor89only when the paper500ais conveyed in the direction A, and to be free to rotate when the paper500ais conveyed in the direction B reverse to the direction A.

The first contact mechanism40can bring the paper500ainto close contact with the conveyor belt33. As shown inFIG. 2, the first contact mechanism40includes a first pressing roller41, a first arm pair42constituted by two arms42aand42bhaving the same shape, a nearly triangular first cam43, and a first spring44for biasing the arm pair42.

The pressing roller41is cylindrical and has its axis of rotation parallel to the width of the printer10. The length of the pressing roller41is substantially equal to the width of the conveyor belt33.

A shaft46is disposed between one ends of the arms42aand42bof the arm pair42. The shaft46is fixed to a proper member in the printer10. The pressing roller41is disposed between the other ends of the arms42aand42b. Each of the arms42aand42bis bent at a position between both ends. The shaft46is parallel to the width of the printer10, like the pressing roller41. The arm pair42rotatably supports the pressing roller41. The arm pair42can rotate around the shaft46.

The cam43is disposed under one arm42bof the arm pair42between the shaft46and the bent position of the arm42b. The cam43can rotate around a rotational axis43a deviated from the center of the cam43.

The spring44is disposed on a side upper face of the one arm42bof the arm pair42between the shaft46and the bent position of the arm42b. The spring44is always biasing the arm pair42such that the pressing roller41can get near to the conveyor belt33. More specifically, the spring44is biasing the arm pair42such that the arm pair42can rotate clockwise inFIG. 1around the shaft46.

In the state shown inFIGS. 1 and 2, the cam43is separated from the arm42b. In this State, the spring44is biasing the arm pair42such that the arm pair42can rotate clockwise inFIG. 1around the shaft46, and the pressing roller41is at a position where it can press the paper500aonto the conveyor belt33.

A first cam motor93shown inFIG. 3connected to the cam43is driven to rotate the cam43counterclockwise inFIG. 1. Thereby, a tapered end of the cam43is brought into contact with the lower face of the arm42b. The cam43is further rotated counterclockwise with its tapered end sliding on the lower face of the arm42b. Thereby, two arms42aand42bof the arm pair42are rotated counterclockwise together. As a result, the other ends of the arm pair42, between which the pressing roller41is supported, are moved upward so that the pressing roller41is distant from the paper500aand the conveyor belt33, as shown inFIG. 5A.

Afterward, the cam43is further rotated counterclockwise inFIG. 1. Thereby, the cam43is separated from the arm42b. The arm pair42is rotated clockwise by the biasing force of the spring44, and the other ends of the arm pair42, between which the pressing roller41is supported, are moved downward. Thereby, the pressing roller41comes again to the position where it can press the paper500aonto the conveyor belt33, as shown inFIGS. 1 and 2.

As shown inFIG. 1, a sensor17for detecting the paper500ais disposed at a position opposed to the conveyor belt33between the first contact mechanism40and the heads12. Detection information of the sensor17is used for determining the start timing for image recording by the heads12, and so on. The sensor17is a photo sensor including a light emitting element and a light receiving element. The sensor17detects the paper500aon the basis of the difference in intensity of reflection light between the paper500aand the conveyor belt33.

Four heads12are arranged in the direction A close to each other. Each head12has at its lower end a head main body12amade up of a flow passage unit and an actuator unit bonded to each other. The flow passage unit includes therein ink flow passages each including a pressure chamber. The actuator unit applies pressure to ink in each pressure chamber. Each head main body12ais rectangular in section. The length of each head main body12ais parallel to the width of the printer10. The bottom face of each head main body12ais formed into an ink ejection face12bwhere a large number of nozzles are formed though the nozzles are not shown inFIG. 1. Four head main bodies12aeject inks of magenta (M), yellow (Y), cyan (C), and black (B), respectively.

Each head main body12ais disposed such that its ink ejection face12bis parallel to the paper conveyance face of the conveyor belt33and a narrow space is formed between the ink ejection face12band the paper conveyance face of the conveyor belt33. The paper conveyance path is formed in the space. While the paper500aput on the conveyor belt33passes immediately below four head main bodies12ain order, ink of each color is ejected from nozzles toward the upper face of the paper500a. Thus, a desired color image is recorded on the paper500a.

As shown inFIGS. 1 and 2, the conveyor unit30includes two belt rollers31and32, a looped conveyor belt33wrapped around the belt rollers31and32to be stretched between the belt rollers31and32, and a substantially rectangular parallelepiped belt guide37disposed within the region surrounded by the conveyor belt33. The belt guide37has substantially the same width as the conveyor belt33. The upper face of the belt guide37is in contact with the inner circumferential surface of the conveyor belt33to support the conveyor belt33.

The material of the conveyor belt33is not particularly limited. For example, the conveyor belt33may be made of silicone rubber, EPDM, urethane rubber, butyl rubber, or the like. The outer circumferential surface of the conveyor belt33has been treated with adhesive silicone rubber, on which surface the paper500ais put.

As shown inFIG. 2, the belt rollers31and32have cylinders31aand32ato be in contact with the inner circumferential surface of the conveyor belt33, and flanges31band32bprovided at both ends of the cylinders31aand32a, respectively. The belt rollers31and32are rotatably supported through not-shown shafts attached to the centers of the respective flange portions31band32b. The flange portions31band32bhave their radius substantially equal to the sum of the thickness of the conveyor belt33and the radius of the cylinders31aand32a.

One belt roller31disposed on the front side is a drive roller connected to a conveyor motor87shown inFIG. 3. When the belt roller31is rotated by drive of the conveyor motor87, the conveyor belt33is driven to rotate. Attendant upon the rotation of the conveyor belt33, the other belt roller32as a follower is rotated.

As shown inFIGS. 1 and 2, a peeling plate39is disposed ahead of the conveyor belt33. The peeling plate39peels the paper500a, which is in close contact with the conveyor belt33, off the conveyor belt33.

The second contact mechanism60can bring the paper500ainto close contact with the conveyor belt33, like the first contact mechanism40. As shown inFIG. 2, the second contact mechanism60includes a second pressing roller61, a protrusion pair62constituted by two protrusions62aand62bformed on two arms65aand65bconstituting a second arm pair65, a nearly triangular second cam63, and a second spring64for biasing the arm pair65.

The pressing roller61is cylindrical and has its axis of rotation parallel to the width of the printer10. The length of the pressing roller61is substantially equal to the width of the conveyor belt33.

Two arms65aand65bconstituting the arm pair65are made of slender members having the same shape. A shaft66is disposed between one ends of the arms65aand65b. The shaft66is fixed to a proper member in the printer10. The shaft66is parallel to the width of the printer10, like the pressing roller61.

The arms65aand65bhave the protrusions62aand62bbetween both ends of the arms65aand65b, respectively. The protrusions62aand62bprotrude somewhat obliquely relatively to the width of the arms65aand65b. The arms65aand65bhave bent portions72aand72bnear the front ends of arms65aand65b, respectively. The arms65aand65bare bent at the bent portions72aand72bto the direction substantially parallel to the protrusions62aand62b. The pressing roller61is rotatably supported between the protrusions62aand62b. A movable roller71of the curl correcting mechanism70is rotatably supported between the bent portions72aand72b. When the arm pair65is rotated around the shaft66, the pressing roller61supported by the protrusion pair62and the movable roller71supported by the bent portion pair72are moved accordingly.

The cam63has substantially the same construction as the above-described first cam43. The cam63is disposed under one arm65bof the arm pair65between the protrusion62band the bent position72b. The cam63can rotate around a rotational axis63adeviated from the center of the cam63.

The spring64is disposed on a side upper face of the one arm65bof the arm pair65between the protrusion62band the bent position72b. The spring64is always biasing the arm pair65such that the arm pair65can rotate clockwise inFIG. 1around the shaft66. That is, the spring64is biasing the arm pair65such that the pressing roller61can get near to the conveyor belt33and the movable roller71can get near to a fixed roller73.

The curl correcting mechanism70corrects the tendency to curl, in the vicinity of the leading edge of the paper500a. As shown inFIG. 2, the curl correcting mechanism70includes a movable roller71, a fixed roller73, and a bent portion pair72constituted by the above-described bent portions72aand72bof the respective arms65aand65b.

Either of the movable and fixed rollers71and73is cylindrical and has its axis of rotation parallel to the width of the printer10. The length of each of the movable and fixed rollers71and73is substantially equal to the width of the conveyor belt33. The movable roller71is made of a plastic material such as stainless steel. The fixed roller73is made of an elastic material such as sponge. The movable roller71is disposed so as to be opposed to the upper surface of the paper500awhile the fixed roller73is disposed such that its outer circumferential surface can be in contact with the back surface of the paper500a.

In the state shown inFIGS. 1 and 2, the cam63is held in a state that a tapered end of the cam63faces upward and is in contact with the lower face of the arm65b. In this state, the arm pair65is held at a position where the pressing roller61is distant from the paper500aand the conveyor belt33and the movable roller71is distant from the fixed roller73.

A second cam motor95shown inFIG. 3connected to the cam63is driven to rotate the cam63counterclockwise inFIG. 1. Thereby, the cam63is separated from the arm65b. The arm pair65is rotated clockwise by the biasing force of the spring64. The protrusion pair62, between which the pressing roller61is supported, and the bent portion pair72, between which the movable roller71is supported, are moved downward together. Thereby, the pressing roller61comes to a position where the pressing roller61can press the paper500aonto the conveyor belt33, and the movable roller71comes to a position where the movable roller71can cooperate with the fixed roller73to pinch the paper500a, as shown inFIG. 5D.

Afterward, the cam63is further rotated counterclockwise inFIG. 1. Thereby, the tapered end of the cam63is brought into contact with the lower face of the arm65b. The cam63is further rotated counterclockwise with its tapered end sliding on the lower face of the arm65b. Thereby, two arms65aand65bof the arm pair65are rotated counterclockwise together. As a result, the pressing roller61is again distant from the paper500aand the conveyor belt33and the movable roller71is also again distant from the fixed roller73, as shown inFIGS. 1 and 2.

As shown inFIG. 1, the cutting mechanism50includes a movable edge51, a fixed edge52, and an actuator53vertically movable with supporting the movable edge51.

The movable edge51has its width larger than the paper500a. The movable edge51has an edge face inclined relatively to a horizontal plane. The movable edge51is fixed to the actuator53at a position above the conveyance path of the paper500asuch that the edge face of the movable edge51faces downward. The fixed edge52has substantially the same width as the movable edge51. The fixed edge52is fixed at a position below the conveyance path of the paper500asuch that an edge face of the fixed edge52faces upward.

The actuator53is moved downward and upward by the drive of a cutter motor91shown inFIG. 3so that the paper500ais cut at a position where the movable edge51overlaps the fixed edge52. The timings for cutting are controlled by a controller80as will be described later.

Next, an electrical construction of the printer10including the controller80will be described with reference toFIG. 3.

The controller60includes a CPU (Central Processing Unit)81, a ROM82storing therein programs and data for the CPU81to perform controlling operations, and a RAM83as a temporarily storing memory.

The CPU81, the ROM82, and the RAM83included in the controller80are connected to an input/output interface84through data buses. The input/output interface84is connected to a head driver85for driving the heads12; a motor driver86for driving the conveyor motor87; a motor driver88for driving the paper feed motor89; a motor driver90for driving the cutter motor91; a motor driver92for driving the first cam motor93; a motor driver94for driving the second cam motor95; a sensor17; and an external interface for communicating with the outside to exchange various data such as image data. The divers, the sensor, etc., can exchange signals with the controller80through the input/output interface84.

The CPU81prepares printing data on the basis of a printing instruction signal received via the external interface96. On the basis of the printing data, the CPU81controls the above drivers to operate.

The controller80functions as an image recording controller for controlling the heads12to record an image on the paper500abeing conveyed in the direction A; a contact operation controller for controlling the operations of the first and second contact mechanisms40and60; a conveyor controller for controlling the conveyor unit30to switch over the conveyance direction of the paper500aput on the conveyor belt33between the directions A and B; a cutter controller for controlling the movable edge51to cut the paper500abeing conveyed in the direction A, at a desired position; and so on.

Next, operations of components in the vicinity of the conveyor unit30in the printer10will be described with reference toFIGS. 4, and5A to5D. The operations of the components as will be described below are controlled by the controller80shown inFIG. 3.

Before printing, as shown inFIG. 5A, the cams43and63of the first and second contact mechanisms40and60are held in a state that both the tapered ends of the cams43and63face upward and are in contact with the lower faces of the arms42band65bshown inFIG. 2. At this time, the first arm pair42is held at a position where the first pressing roller41is distant from the paper500aand the conveyor belt33. The second arm pair65is held at a position where the second pressing roller61is distant from the paper500aand the conveyor belt33and the movable roller71is distant from the fixed roller73. The leading edge of the paper500ais at a position near the paper feed roller15of the paper feed unit14, and has not yet reached the paper conveyance path on the conveyor belt33.

For printing, first, the first pressing roller41of the first contact mechanism40is moved downward, in Step S101. More specifically, the first cam motor93shown inFIG. 3is driven so that the first cam43is rotated counterclockwise from the state shown inFIG. 5Aand thereby separated from the arm42bshown inFIG. 2. Thereby, as shown inFIG. 5B, the arm pair42is rotated clockwise by the biasing force of the spring44so that the other ends of the arm pair42, between which the pressing roller41is supported, are moved downward. The pressing roller41then comes to the position where it can press the paper500aonto the conveyor belt33.

Next, the conveyor motor87shown inFIG. 3is driven to start normal rotation of the conveyor belt33, in Step S102. The term “normal rotation” means that the belt roller31as the drive roller is rotated clockwise as shown inFIG. 5Band the upper part of the conveyor belt33runs in the direction A.

Afterward, the paper feed motor89shown inFIG. 3is driven to start rotation of the paper feed roller15, in Step S103. By the rotation of the paper feed roller15, the paper500ais conveyed in the direction A and its leading edge reaches the paper conveyance path on the conveyor belt33. When the paper500areaches the position where the first contact mechanism40can bring the paper500ainto close contact with the conveyor belt33, that is, the position where the first pressing roller41is disposed, the first pressing roller41, which has been brought to the position where it can press the paper500aonto the conveyor belt33, presses the paper500aonto the conveyor belt33. Thus, the paper500ais conveyed with being in close contact with the conveyor belt33.

After the rotation of the paper feed roller15is started, a paper detecting operation of the sensor17is started. The detection information of the sensor17is sent to the CPU81shown inFIG. 3. The CPU81judges in Step S104whether or not the sensor17has detected the paper500a. If the paper500ahas not yet been detected, that is, NO in Step S104, the CPU81judges whether or not a predetermined time period has elapsed, in Step S105.

If the predetermined time period has elapsed, that is, YES in Step S105, the CPU81judges the condition to be “error”. In this case, the first pressing roller41of the first contact mechanism40is moved upward, in Step S106, so that the pressing roller41is again distant from the paper500aand the conveyance belt33as shown inFIG. 5A, and then the operations of the components of are ended. This case may occur, for example, when the paper500ais not adequately conveyed.

In the case that the paper500ais adequately conveyed in the direction A with being in close contact with the conveyor belt33after the rotation of the paper feed roller15is started, the sensor17detects the paper500awithin the predetermined time period. When the paper500ais detected, that is, YES in Step S104, the rotation of the paper feed roller15is stopped, in Step S107. The CPU81controls the drive of the heads12on the basis of the printing data prepared as described above, to record an image on the paper500abeing conveyed, in Step S108.

After completion of image recording by the heads12, the CPU81shown inFIG. 3judges in Step S109whether or not the portion of the paper500adistant by a predetermined distance from the rearmost end of the region where the image has been recorded, has been opposed to the movable and fixed edges51and52of the cutting mechanism50. More specifically, this judgment is made on the basis of the movement distance of the paper500acalculated from the number of revolutions of the conveyor motor87shown inFIG. 3after the completion of image recording.

When the leading edge of the paper500areaches the position where the peeling plate39is disposed, the paper500a, which is in close contact with the conveyor belt33, is peeled off the conveyor belt33by the peeling plate39, and then conveyed to the cutting mechanism50.

When the portion of the paper500ato cut reaches the cutting position by the cutting mechanism50, that is, YES in Step S109, the conveyor belt33is stopped, in Step S110. In this state, as shown inFIG. 5C, the paper500ais cut, in Step S111.

After the cutting operation in Step S111, the part of the paper500ain the rear of the cutting position by the cutting mechanism50and continuous to the roll500is rewound onto the roll500. That is, the paper500ais conveyed in the direction B reverse to the direction A, as shown inFIG. 5D. Immediately after the cutting operation, the leading edge of the paper500ais at the position where the movable and fixed edges51and52of the cutting mechanism50are disposed, distant ahead of the conveyor belt33. The portion of the paper500anear the leading edge has been peeled off the conveyor belt33by the peeling plate39.

Before the rewinding operation, first, the second pressing roller61of the second contact mechanism60and the movable roller71of the curl correcting mechanism70are moved downward, in Step S112. More specifically, the second cam motor95shown inFIG. 3is driven so that the second cam63is rotated counterclockwise from the state shown inFIG. 5Cand thereby separated from the arm65bshown inFIG. 2. Thereby, as shown inFIG. 5D, the arm pair65is rotated clockwise by the biasing force of the spring64so that the protrusion pair62, between which the pressing roller61is supported, and the bent portion pair72, between which the movable roller71is supported, are moved downward together. The second pressing roller61then comes to the position where it can press the paper500aonto the conveyor belt33, and the movable roller71comes to the position where it can cooperate with the fixed roller73to pinch the paper500a.

Next, the first pressing roller41of the first contact mechanism40is moved upward, in Step S113, so that the pressing roller41is again distant from the paper500aand the conveyor belt33. Reverse rotation of the conveyor belt33is then started, in Step S114. The term “reverse rotation” means that the belt roller31as the drive roller is rotated counterclockwise as shown inFIG. 5Dand the upper part of the conveyor belt33runs in the direction B.

After the reverse rotation of the conveyor belt33is started, the paper500ais conveyed in the direction B. The portion of the paper500anear the leading edge, which has been peeled off the conveyor belt33, is pinched by the movable and fixed rollers71and73of the curl correcting mechanism70and thereby the tendency to curl is corrected. The portion of the paper500anear the leading edge is then pressed onto the conveyor belt33by the second pressing roller61of the second contact mechanism60. Thus, the paper500ais conveyed on the conveyor belt33with being in close contact with the conveyor belt33.

After the reverse rotation of the conveyor belt33is started, a paper detecting operation of the sensor17is started. The detection information of the sensor17is sent to the CPU81shown inFIG. 3. The CPU81judges in Step S115whether or not the paper500ahas been undetectable by the sensor17.

When the paper500ahas been undetectable by the sensor17, that is, YES in Step S115, the paper500ais conveyed in the direction B till the leading edge of the paper500areaches a position in the rear of the pressing position by the first pressing roller41of the first contact mechanism40, and then the conveyor belt33is stopped, in Step S116. Because the conveyance of the paper500ais stopped in a state that the leading edge of the paper500ais in the rear of the pressing position by the first pressing roller41as described above, the first pressing roller41can bring the paper500ainto close contact with the conveyor belt33from the leading edge of the paper500ain the next printing operation.

After the conveyor belt33is stopped, the second pressing roller61of the second contact mechanism60and the movable roller71of the curl correcting mechanism70are moved upward, in Step5117. Thereby, the pressing roller61is distant from the paper500aand the conveyor belt33, and the movable roller71is distant from the fixed roller73. Thus, the printer10is again in the state shown inFIG. 5A.

Next, operations of the roll supporting mechanism22and the tensioner26disposed within the cassette20when the roll500starts rotating will be described with reference toFIGS. 6A to 6C.

FIG. 6Ashows a state before the paper500ais conveyed by the above-described Step S103shown inFIG. 4. The paper500awas rewound to the roll500after the last printing operation. At that time, looseness is generated in the portion of the paper500awithin the cassette20. As Steps S101and S102are performed, the paper feed roller15is rotated in Step S103, and thereby the paper500ais being conveyed, the looseness of the paper500agenerated within the cassette20is gradually eliminated.

Simultaneously with elimination of the looseness, the roll500starts to be rotated. At this time, because of a sharp change in tension on the paper500a, a shock may be applied to the paper500a. However, the shock is absorbed by the roll supporting mechanism22and the tensioner26. More specifically, as shown inFIGS. 6B and 6C, because the roll500is supported by the roll supporting mechanism22with suppressing ricketiness and the paper500abeing unwound from the roll500is conveyed with being given a proper tension by the tensioner26, the shock is absorbed.

As described above, in the inkjet printer10of this embodiment, when image recording is performed on the paper500abeing conveyed in the direction A, because the first contact mechanism40brings the paper500ainto close contact with the conveyor belt33, good image recording can be achieved. On the other hand, when the paper500ais conveyed in the direction B reverse to the direction A after image recording and being cut, the second contact mechanism60can bring the portion of the paper500anear its leading edge, which is apt to curve upward due to its tendency to curl, into close contact with the conveyor belt33. Thus, the paper500ais prevented from coming into contact with any head12.

In addition, the first contact mechanism40has a relatively simple construction that includes the first pressing roller41that can be selectively at a position where it can press the paper500aonto the conveyor belt33and at a position where it is distant from the paper500aand the conveyor belt33.

The first contact mechanism40including the first pressing roller41, the first arm42, the first cam43, and the first spring44, can efficiently bring the paper500ainto close contact with the conveyor belt33though the first contact mechanism40has a relatively simple construction.

Before the leading edge of the paper500areaches the position where the pressing roller41of the first contact mechanism40can press the paper500aonto the conveyor belt33, the pressing roller41comes to the position where it can press the paper500aonto the conveyor belt33, in Step S101. Thus, the paper500abeing conveyed in the direction A can be brought into close contact with the conveyor belt33in order from the leading edge of the paper500a. In case that the pressing roller41is moved downward after the leading edge of the paper500areaches the above position, a problem may arise that the portion of the paper500anear the leading edge can not adequately be brought into close contact with the conveyor belt33. In this embodiment, however, the problem can be relieved.

Further, before the paper500acut in Step S111shown inFIG. 4is conveyed in the direction B in Step S114, the first pressing roller41is moved upward to be distant from the paper500aand the conveyor belt33. While the paper500ais conveyed in the direction B, the first pressing roller41is kept distant from the paper500aand the conveyor belt33. For example, in case that the paper500ais conveyed in the direction B in Step S114in a state that the first pressing roller41is at the position where it can press the paper500aonto the conveyor belt33, a bent portion may be formed in the paper500aahead of the first pressing roller41in the direction A due to the friction between the paper500aand the first pressing roller41. The bent portion of the paper500amay come into contact with a head12. However, this embodiment can prevent this.

The second contact mechanism60also has a relatively simple construction that includes the second pressing roller61that can be selectively at a position where it can press the paper500aonto the conveyor belt33and at a position where it is distant from the paper500aand the conveyor belt33.

The second contact mechanism60including the second pressing roller61, the protrusion pair62, the second cam63, and the second spring64, can efficiently bring the paper500ainto close contact with the conveyor belt33though the second contact mechanism60has a relatively simple construction.

Before the paper500astarts to be conveyed in the direction B after the conveyance of the paper500ain the direction A is completed, the pressing roller61of the second contact mechanism60comes to the position where it can press the paper500aonto the conveyor belt33, in Step S112. Thus, the paper500acan be brought into close contact with the conveyor belt33in order from the portion of the paper500acorresponding to the pressing roller61. As a result, the portion of the paper500anear the leading edge can be more surely prevented from coming into contact with a head12in comparison with a case wherein the pressing roller61is moved downward after the paper500astarts to be conveyed in the direction B.

Further, after the conveyance of the paper500ain the direction B in Step S114is completed, the second pressing roller61is moved upward in Step S117to be distant from the paper500aand the conveyor belt33. While the paper500ais conveyed in the direction A, the second pressing roller61is kept distant from the paper500aand the conveyor belt33. For example, in case that the paper500ais conveyed in the direction A in Step S102in a state that the second pressing roller61is at the position where it can press the paper500aonto the conveyor belt33, a bent portion may be formed in the paper500ain the rear of the second pressing roller61in the direction A due to the friction between the paper500aand the second pressing roller61. The bent portion of the paper500amay come into contact with a head12. However, this embodiment can prevent this.

Further, the printer10includes the curl correcting mechanism70ahead of the second contact mechanism60in the direction A. After the paper500astarts to be conveyed in the direction B in Step S114, the curl correcting mechanism70corrects the tendency to curl of the portion of the paper500anear the leading edge before the portion of the paper500areaches the second contact mechanism60. This improves the contactability of the paper500aonto the conveyor belt33, and more surely relieves the above problem that the paper500amay come into contact with a head12.

In the curl correcting mechanism70, the action of the bent portion pair72, between which the movable roller71is rotatably supported, is linked to the action of the second arm, i.e., the protrusion pair61, of the second contact mechanism60through the arm pair65. Therefore, there is no need of special means for controlling the action of the curl correcting mechanism70. In addition, because the second pressing roller61and the movable roller71are moved downward together so that they simultaneously comes to the position where the second pressing roller61can press the paper500aonto the conveyor belt33and the position where the movable roller71can cooperate with the fixed roller71to pinch the paper500a, respectively, as described above and shown inFIGS. 4 and 5D, the number of steps can be decreased.

In addition, because the above bent portion pair72of the curl correcting mechanism70is formed integrally with the protrusion pair62of the second contact mechanism60, the number of parts can be decreased.

Because the movable roller71is made of a plastic material and the fixed roller73is made of an elastic material in the curl correcting mechanism70, the effect of correcting the tendency to curl of the paper500ais further improved.

Further, the printer10includes the roll supporting mechanism22and the tensioner26as a shock absorbing mechanism for absorbing a shock to the paper500a. Thus, the paper500ais prevented from receiving a strong shock, for example, because of a sharp change in tension on the paper500awhen the roll500starts to be rotated.

If such a shock absorbing mechanism is provided in the printer10, there is probability that the paper feed motor89shown inFIG. 3for driving the paper feed roller15is locked due to the shock. In addition, because the conveyance of the paper500ais stopped in a moment, slur may occur and the paper500abeing in close contact with the conveyor belt33may be peeled off the conveyor belt33. In this embodiment, however, because the shock absorbing mechanism including the roll supporting mechanism22and the tensioner26is provided, the above problem can be relieved.

In the above-described embodiment, the roll supporting mechanism22has a construction in which the spring25is attached to one supporting roller24cof three supporting rollers24ato24c. The present invention is not limited to this construction. A spring may be attached also to one or either of the other two supporting roller24aand24b. In addition, the roll supporting mechanism suffice if it can support the roll500so that the roll500can be rotatable and elastically displaceable or rotatable and swingable. Thus, the construction of the roll supporting mechanism is not limited to that including the supporting rollers24ato24cand the spring25.

The shock absorbing mechanism of the printer10may not be made up of both of the roll supporting mechanism22and the tensioner26. The shock absorbing mechanism may be one of the roll supporting mechanism22and the tensioner26. The shock absorbing mechanism may have another construction that brings about an effect of absorbing a shock. Further, the printer10may include no shock absorbing mechanism.

The curl correcting mechanism70may have another construction that brings about a similar effect. For example, the bent portion pair72of the curl correcting mechanism70may not be formed integrally with the protrusion pair62of the second contact mechanism60as in the above-described embodiment. In this case, a gear may be provided at an end portion of the shaft65aof the second arm pair65so that the movable roller71of the curl correcting mechanism70is moved by the rotation of the gear. Further, the curl correcting mechanism70may be omitted.

The timings for moving the pressing roller41of the first contact mechanism40and the pressing roller61of the second contact mechanism60are not limited to those in the above-described embodiment.

In the above-described embodiment, the first and second pressing rollers41and61are moved by the respective first and second cam motors93and95driven under the control of the CPU81. However, the present invention is not limited to that the movements of the first and second pressing rollers41and61are under the control of the CPU81. For example, notched gears may be used that drive the first and second pressing rollers41and61in accordance with the normal and reverse revolutions of the conveyor motor87and do not transmit the driving force of the conveyor motor87at predetermined rotational positions of the gears.

The conveyor belt33may be manually reversed so that the second pressing roller61and the movable roller71are moved down in accordance with the manual operation.

In the above-described embodiment, the position where the first pressing roller41can press the paper500aonto the conveyor belt33is opposed to the guide member37. However, the positional relation may be changed according to circumstances.

In the above-described embodiment, the position where the second pressing roller61can press the paper500aonto the conveyor belt33is opposed to the belt roller31. However, the positional relation may be changed according to circumstances.

The first and second contact mechanisms40and60have the constructions in which the first and second pressing rollers41and61press the paper500aonto the conveyor belt33, respectively. However, the present invention is not limited to those. For example, in any of the mechanisms, the paper500amay be brought into close contact with the conveyor belt33by air pressure.

The conveyor unit30is not limited to the construction in which the paper is conveyed by the conveyor belt33. For example, the paper500amay be put on a cylindrical drum to convey.

In the above-described embodiment, the cutting mechanism50includes the movable and fixed edges51and52. However, the present invention is not limited to this. For example, a so-called rotary cutter that can cut the paper500awith a rotating edge may be used as the cutting mechanism. Further, the printer10may include no cutting mechanism. In that case, for example, the paper500adischarged out of the printer10may be cut with scissors or the like, in Step S111. Afterward, instructions may be given to the printer10through a not-shown input unit to rewind the paper500a.

The roll500may be formed by winding the paper500aon a cylindrical core.

The number of heads in the printer is not limited to four. Further, the printer is not limited to a color printer.

The present invention is not limited to inkjet printers. For example, the present invention is applicable also to inkjet type facsimiles and copying machines.