Patent Application
20090212490
This application is based upon and claims priority from Japanese Patent Application No. 2007-310043 filed on Nov. 30, 2007, the entire contents of which are incorporated herein by reference.
This invention relates to a sheet end detection device for detecting an end of a sheet such as a recording sheet to be conveyed, an image recording apparatus including the sheet end detection device, and a method for detecting an end position of a conveyed sheet using the sheet end detection device.
An image recording apparatus for forming an image on a recording sheet, such as an ink jet printer needs to precisely keep track of the position of a sheet end to form an image at any desired position on the plane (space) of the recording sheet. Particularly, there has been a need for more precisely keeping track of the position of a sheet end in borderless printing of a photo, etc., needed increasingly in recent years. That is, in the borderless printing, a predetermined margin is provided from the sheet end of a recording sheet, and a slightly wider print area is set than the area of the recording sheet, thereby forming an image with no blank at the sheet ends. At this time, since the print area which is set for the borderless printing includes an outside area of the recording sheet, ink is also ejected to the outside area of the recording sheet and is not supplied to image formation, which goes to waste and makes dirt the periphery of a platen for supporting the recording sheet, etc. For the image formed on the recording sheet, the surrounding image is lost. In contrast, it the position of a sheet end can be kept track of more precisely, the margin size can be decreased, and the area of the recording sheet and the set print area can be more matched with each other. Therefore, waste of ink, occurrence of peripheral contamination, loss of the surrounding image, and the like as described above can be suppressed.
To detect an end part of a recording sheet, a method of providing a moving arm at a midpoint in a conveying passage of a recording sheet, detecting fluctuation of the moving arm caused by contact with the conveyed recording sheet with an infrared sensor, and detecting the leading end of the recording sheet has been known. However, when the recording sheet is conveyed in a floating attitude from the conveying passage in a direction normal to the sheet plane, a timing of contacting with the arm varies, and the thickness and the material of the recording sheet, etc., have an influence on the detection accuracy. Therefore, it is difficult to improve the detection accuracy. Further, in the method, the sheet end in the direction orthogonal to the conveying direction of the recording sheet (side end) cannot be detected.
JP-A-7-215528 (especially,
However, in the configuration according to JP-A-7-215528, the piezoelectric element group including six piezoelectric elements is disclosed in an embodiment, and thus the position of a side end of the recording sheet can be detected in only six ways and the detection accuracy is low. Although the detection accuracy can be improved by increasing the number of arranged piezoelectric elements, a considerable number of minute piezoelectric elements independent of one another need to be provided to realize the detection accuracy at a level demanded in the borderless printing as described above; it is not realistic considering the labor and the cost at the manufacturing time.
Such circumstances is applied not only to the ink jet printer, but also to other printers such as a thermal printer, etc., and a copier and a facsimile machine. Further, in addition to a recording sheet to record an image, to detect the position of a sheet with an image recorded thereon in a scanner for reading an image and converting it into an electric signal, it is also necessary to precisely detect an end position of the sheet; similar circumstances to those described above exist.
It is therefore an object of the invention to provide a sheet end detection device that can be easily manufactured and can suppress the manufacturing cost while more precisely detecting the end position (particularly, side end position) of a sheet to be conveyed such as a recording sheet, an image recording apparatus including the sheet end detection device, and a method for detecting an end position of a sheet using the sheet end detection device.
According to a first aspect of the invention, there is provided A sheet end detection device comprising: a cylindrical roller rotatable around an axis with conveying of a sheet to be conveyed in a state in which a peripheral surface of the roller contacts one face of the conveyed sheet; and a phase detection unit configured to detect a phase in a circumferential direction of the roller, wherein a first piezoelectric element band is provided on the peripheral surface of the roller and extending in the circumferential direction and the axial direction, the first piezoelectric element band being configured to detect a contact of the sheet and extending in an axial direction of the roller over an inside and an outside of a contact area to be contacted with the conveyed sheet on the peripheral surface, and wherein a position of an arbitrary point of the first piezoelectric element band in the axial direction of the roller corresponds one-to-one with the phase in the circumferential direction of the roller.
According to a second aspect of the invention, there is provided an image recording apparatus comprising: a sheet end detection device according to the first aspect of the invention; and a recording head for ejecting ink to a recording sheet as the conveyed sheet to form an image, wherein the roller is provided at a midpoint in the conveying passage of the sheet to be conveyed.
According to a third aspect of the invention, there is provided a method for detecting an end position of a sheet using the sheet end detection device according to the first aspect, said method comprising: detecting the phase of the roller by the phase detection unit; detecting a contact state indicating whether the first piezoelectric element band with the sheet; detecting the end position of the sheet in a direction orthogonal to the conveying direction by, when the first piezoelectric element band detects change in the contact state, a position of the roller in the axial direction at which the contact state is changed based on the phase of the roller detected by the phase detection unit.
An image recording apparatus including a sheet end detection device according to an embodiment of the invention will be discussed specifically below with reference to the accompanying drawings.
(Image Recording Apparatus)
The image recording apparatus 1 is connected to an external information machine such as a personal computer and records an image of text, a photo, a paint graph, etc., on a recording sheet P as a recording sheet based on data transmitted from the computer, etc. To connect a digital camera, etc., to the image recording apparatus 1, the image recording apparatus 1 can also record a photo on a recording sheet P based on data output from the digital camera, etc.; to place any storage medium of a memory card, etc., in the image recording apparatus 1, the image recording apparatus 1 can also record an image on a recording sheet P based on data recorded on the storage medium. To record an image of a photo, etc., borderless printing with no blank in a margin of a recording sheet P can be executed.
As shown in
A door 7 is provided in the lower right portion of the front of the printer unit 2 as it can be opened and closed. Provided inside with the door 7 open is a housing room in which a main tank (ink cartridge) 9 (see
The scanner unit 3 provided in the upper part of the image recording apparatus 1 is implemented as a flatbed scanner. That is, as shown in
An operation panel 11 for operating the printer unit 2 and the scanner unit 3 is provided on the front top of the image recording apparatus 1. The operation panel 11 includes various operation buttons and a liquid crystal display and the image recording apparatus 1 can operate based on a command output from the operation panel 11 as the user operates the operation panel 11. If the image recording apparatus 1 is connected to an external computer, the image recording apparatus 1 also operates based on a command transmitted from the computer through a printer driver or a scanner driver.
A slot unit 12 is provided in the upper left portion of the front of the image recording apparatus 1. Any of various small memory cards of storage media can be placed in the slot unit 12. The user performs predetermined operation through the operation panel 11, whereby data stored on the small memory card placed in the slot unit 12 can be read. The read data can also be displayed on the liquid crystal display of the operation panel 11 and any image selected based on the display can be recorded on a recording sheet P on the printer unit 2.
A sheet feed roller 26 for feeding a recording sheet P in the sheet feed tray 5 to the conveying passage 23 is provided just above the sheet feed tray 5. A conveying roller pair 29 including a conveying roller 27 and a driven roller 28 described later is provided so as to sandwich the conveying passage 23 from up and down between the rollers 27 and 28 in the proximity of the downstream portion of the bend path 24 in the conveying passage 23. The conveying roller pair 29 forms apart of a sheet end detection unit 40 for detecting an end part position of a recording sheet P as described later (also see
Further, a sheet discharge roller pair 32 including a sheet discharge roller 30 and a pinch roller 31 is provided so as to sandwich the conveying passage 23 from up and down between the rollers 30 and 31 in the proximity of the downstream portion of the straight path 25 in the conveying passage 23. The recording head 20 and the platen 18 are provided so as sandwich the straight path 25 from up and down between the conveying roller pair 29 and the sheet discharge roller pair 32.
Therefore, a recording sheet P in the sheet feed tray 5 is fed to the conveying passage 23 by the sheet feed roller 26 and subsequently is conveyed from the bend path 24 to the straight path 25 on the conveying passage 23 by the conveying roller pair 29. An image is recorded on the space of the recording sheet P arriving at the straight path 25 in ink ejected from the recording head 20 and upon completion of the recording, the recording sheet P is ejected from the straight path 25 by the sheet discharge roller pair 32 and is housed in the sheet discharge tray 6 (see
As shown in
In the image recording apparatus 1 as described above, the conveying roller pair 29 provided at a midpoint in the conveying passage 23 includes the function of conveying the conveyed recording sheet P further to the downstream portion; in addition, in the embodiment, the conveying roller pair 29 forms a part of the sheet end detection unit 40 for detecting an end part position of the recording sheet P. The configuration of the sheet end detection unit 40 will be discussed below:
(Sheet End Detection Unit)
The conveying roller 27 is provided on a-peripheral surface 27b with a first piezoelectric element band 42.
When the recording sheet P conveyed on the conveying passage 23 goes as it is sandwiched between the conveying roller 27 and the driven roller 28, it passes through a position to one side in the direction of the axis 27a and a contact area 43 (area surrounded by the alternate long and two short dashes line in
A surface electrode extending along the first piezoelectric element band 42 shaped like a metal band is deposited on the surface of the first piezoelectric element band 42 and forms an opposite electrode 44b of the first piezoelectric element band 42. Further, an insulating thin film cover 45 containing alumina, etc., is provided so as to cover the first piezoelectric element band 42 and the electrode 44b. Therefore, if any point of the first piezoelectric element band 42 is pressed through the cover 45 and the electrode 44b, an electromotive force occurs at the pressed point because of the piezoelectric effect and a pulse signal formed by the electromotive force is output through the electrode 44a, 44b. Such a pulse signal and a detection signal from the encoder 41 are input to a controller 50 included in the image recording apparatus 1.
The first piezoelectric element band 42 containing piezoelectric elements described above can be formed easily on the peripheral surface 27b of the conveying roller 27 by an aerosol deposition method (AD method). An outline of the forming method of the first piezoelectric element band 42 by the AD method is given below: The peripheral surface 27b of the conveying roller 27 is covered with a mask so as to expose only the area to form the first piezoelectric element band 42, the conveying roller 27 in this state is held in a chamber, and this chamber is decompressed. Next, ceramics material powder entered in a storage vessel is mixed with a carrier gas to produce aerosol material, which is then introduced into a nozzle provided in the decompressed chamber. The aerosol ceramics material powder is ejected at high speed toward the conveying roller 27 from the nozzle using a pressure difference between the chamber inside and the nozzle inside and is brought into collision with the peripheral surface 27b to form a film.
The conveying roller 27 is rotated around the axis 27a using appropriate drive means while the ceramics material powder is ejected to the conveying roller 27, whereby the ceramics material powder can be brought into collision with the full face of the peripheral surface 27b and the first piezoelectric element band 42 can be formed over the overall length where it is required.
A drive unit 53 including a motor, a driver circuit, etc., is connected to the processor 51. The drive unit 53 drives in accordance with a command from the processor 51, whereby the conveying roller 27 rotates around the axis 27a for conveying the recording sheet P along the conveying passage 23. Further, the encoder 41 and the first piezoelectric element band 42 described above are connected to the processor 51. A detection signal from the encoder 41 and a pulse signal from the first piezoelectric element hand 42 are input to the processor 51.
The sheet end detection unit 40 included in the image recording apparatus 1 having the configuration as described above inserts the recording sheet P conveyed along the conveying passage 23 into the nip between the conveying roller 27 and the driven roller 28 and further conveys the recording sheet P downstream. At this time, the sheet end detection unit 40 detects the side end position of the recording sheet P. The detection method will be discussed below;
To begin with, the case shown in
In the case shown in
Then, at the time of the end of the first rotation of the conveying roller 27 (phase 2π), the recording sheet P and the first piezoelectric element band 42 are once brought out of contact with each other (noncontact state) and thus the signal from the first piezoelectric element band 42 makes an on to off transition. Subsequently, when the conveying roller 27 becomes phase A4 (≦A3+2π) at the second revolution, side end position P4 of the recording sheet P comes in contact with the first piezoelectric element band 42 and the signal from the first piezoelectric element band 42 again makes an off to on transition. Therefore, also in the contact mode shown in
Thus, in the sheet end detection unit 40 according to example 1, in both the contact modes in
Thus, the sheet end detection unit 40 according to example 1 can detect the side end position of the recording sheet P. As for the detection accuracy, the side end position is detected based on the phase of the conveying roller 27 at the contact time between the first piezoelectric element band 42 and the recording sheet P, so that the side end position can be detected with very high accuracy as compared with the related arts.
There is a possibility that the signal may make a second off to on transition at the second revolution of the conveying roller 27 since the conveying roller 27 and the recording sheet P started to come in contact with each other as shown in
It is desirable that a plurality of recording sheets P conveyed consecutively on the conveying passage 23 should be conveyed with a spacing of the outer peripheral dimension L1 of the conveying roller 27 or more from each other. In so doing, after completion of detection of the side end position about the first recording sheet P, it is confirmed that a signal indicating change in the contact state is not input from the first piezoelectric element band 42 during one revolution of the conveying roller 27, whereby it can be determined that the first recording sheet P has passed through the conveying roller pair 29. Therefore, then, if a signal indicating change in the contact state from the first piezoelectric element band 42 is detected, the signal is assumed to be the signal first making an off to on transition (signal occurring in phase A1, A3 in
Therefore, only the first piezoelectric element band 62 will be discussed and components identical with or similar to those of the sheet end detection unit 40 previously described with reference to the accompanying drawings are denoted by the same reference numerals and will not be discussed again.
As shown in the developed view of
To begin with, the case shown in
In the case shown in
Thus, in the sheet end detection unit 60 according to example 2, in both the contact modes in
Thus, the sheet end detection unit 60 according to example 2 can also detect the side end position of the recording sheet P. As for the detection accuracy, the side end position is detected based on the phase of the conveying roller 61 at the contact time between the first piezoelectric element band 62 and the recording sheet P, so that the side end position can be detected with very high accuracy as compared with the related arts, as with the configuration of example 1.
As shown in
Thus, the sheet end detection unit 70 including the second piezoelectric element band 72 in addition to the first piezoelectric element band 42 can detect not only the side end position of the recording sheet P according to the first piezoelectric element band 42, but also the leading end position of the recording sheet P according to the second piezoelectric element band 72. Therefore, the four corner positions of a general recording sheet P shaped like a rectangle on a plan view can be detected precisely.
In
As shown in
To begin with, the case shown in
In the case shown in
Thus, in the sheet end detection unit 90 according to example 4, in both the contact modes in
The mode in which the signal from the first piezoelectric element band 92 initially makes an off to on transition, the first piezoelectric element band 92 and the side end of the recording sheet P come in contact with each other is similar to that of the sheet end detection unit 60 in example 2. Therefore, the operation of the controller 50 based on the method described above using the sheet end detection unit 90 according to example 4 is similar to the operation previously described with reference to the flowchart of
In the above-described example 1 to 4, one first piezoelectric element band is provided on the peripheral surface 27b of the roller 27. However, as shown in
In the example shown in
The range of each of the first piezoelectric element bands 142a to 142d in the X-axis direction may be set according to the size of the recording sheet to be conveyed. In this case, the first piezoelectric element bands 142a to 142d are provided for detecting the end positions of the recording sheets of first to fourth sizes, respectively. For example, the first piezoelectric element band 142a is provided for detecting the end position of the recording sheet of A4 size, and the first piezoelectric element band 142b is provided for detecting the end position of the recording sheet of B5 size. In other words, the first piezoelectric element bands 142a to 142d are provided on the peripheral surface inside and outside the contact area to the recording sheets of respective sizes. One example of the end positions of the recording sheets of the respective sizes is shown by chain lines “a” to “d.”
The method for detecting the end position of the recording sheet using each of the piezoelectric element bands 142a to 142d are similar to the above-described examples. Further, when the size of the recording sheet to be conveyed is designated by the operation panel 11, only one of the piezoelectric element bands 142a to 142d corresponding to the designated size may be used for detecting the end position of the recording sheet. For example, if A4 size is designated, the controller 50 may detect the end position of the recording sheet based on only the output from the piezoelectric element band 142a. On the other hand, the controller 50 may detect the end position of the recording sheet based on the combination of the signals output from the piezoelectric element bands 142a to 142d. For example, when the controller 50 detects the ON signals output from the piezoelectric element bands 142b to 142d and does not detect the ON signal from the piezoelectric element bands 142a, the controller 50 determines the recording sheet is B5 size and detects the end position by using the signal output from the piezoelectric element band 142b.
Although the example of
By the way, in examples 1 to 4 described above, the sheet end detection unit 40, 60, 70, 80, 90 provided in the printer unit 2, namely, the sheet end detection unit 40, etc., for detecting the position of a recording sheet when the image recording apparatus 1 executes the printer function, the copy function, or the facsimile function has been described, but can also be adopted for detecting the position of a sheet fed in a scanner having an automatic sheet feed function.
The first piezoelectric element band 42, 62, 92 need not be linear as shown in the developed view and may be any other form if the position in the direction along the axis 27a of the conveying roller 27, etc., and the phase around the axis 27a are in a one-to-one correspondence with each other about an arbitrary point in the extension direction of the first piezoelectric element band 42, etc. Further, the positions of the start point and the end point of the second piezoelectric element band 72, 82 as shown in
In the examples described above, the first piezoelectric element band 42, 62, 72, 82, 92 including piezoelectric elements has been described, but the invention is not limited to the mode. For example, a pressure sensitive capacity change material involving correlation between given pressure and output potential can also be used even if it is a material different from piezoelectric elements. As the material, for example, a pressure sensitive material manufactured by EMFIT with a large number of air bubbles formed in a resin of polypropylene (PP), etc., can be adopted. If the material is formed of a film and the film is pressurized from both faces, a charge move occurs in the material and a potential difference occurs between both the faces. Thus, change in the potential difference is detected, whereby an end part of a recording sheet P can be detected.
As a material capable of detecting pressure change on a different principle from piezoelectric elements, a pressure sensitive conductive material involving correlation between given pressure and conductivity (resistance value) can also be used. As the material, a material called inustomer (registered trademark) with conductive particles dispersed and mixed into an insulating polymer can be adopted. If the material is formed of a film and the film is pressurized from both faces, the conductive particles in the material come in contact with or are brought close to each other, whereby the electric resistance value between both the faces lowers. Thus, change in the electric resistance value is detected, whereby an end part of a recording sheet P can be detected.
Each piezoelectric element adopted in the embodiment has high rigidity as compared with the pressure sensitive material manufactured by EMFIT and inustomer (trade name) and thus has the advantage that when it comes in contact with a recording sheet P, deformation of the element is small and the influence on conveying the recording sheet P is small.
The invention can be applied to a sheet end detection device that can be easily manufactured and can suppress the manufacturing cost while detecting the end position (particularly, side end position) of a conveyed sheet such as a recording sheet, an image recording apparatus including the sheet end detection device, and an end position detection method of a recording sheet using the sheet end detection device.
In the above embodiment, a sheet end detection device includes a cylindrical roller being provided at a midpoint in a conveying passage of a conveyed sheet and capable of rotating around an axis with conveying of the conveyed sheet in a state in which a peripheral surface comes in contact with one face of the conveyed sheet and a phase detection unit for detecting a phase around the axis of the roller, wherein the roller is provided on the peripheral surface with a first piezoelectric element band shaped like a band for detecting contact with the conveyed sheet so as to make a round around the axis while extending in the axial center direction over the inside and the outside of a contact area with the conveyed sheet on the peripheral surface, and wherein the first piezoelectric element band is formed so that the axis direction position of the roller at an arbitrary point in the extension direction of the first piezoelectric element band and the phase around the axis of the roller are in a one-to-one correspondence with each other.
In an end position detection method of a conveyed sheet according to the embodiment using the sheet end detection device, based on the phase of the roller indicated by the phase detection unit when the first piezoelectric element band detects change in a contact state with the conveyed sheet, the axis direction position of the roller is acquired about the change position of the contact state with the conveyed sheet, thereby detecting the end position in a direction orthogonal to the conveying direction of the conveyed sheet.
With the sheet end detection device as described above, to detect contact with the conveyed sheet, the first piezoelectric element band shaped like a band is provided on the peripheral surface of the roller for rotating with conveying of the conveyed sheet, so that it is not necessary to provide a considerable number of piezoelectric elements and the sheet end detection device can be easily manufactured and the manufacturing cost can also be suppressed. The end part in the direction orthogonal to the conveying direction of the conveyed sheet (side end) can also be detected with high accuracy.
That is, according to the end position detection method of a conveyed sheet using the sheet end detection device described above, the contact position with the conveyed sheet in the first piezoelectric element band, more particularly, the axis direction position of the roller can be detected, so that the side end position of the conveyed sheet can be detected. The first piezoelectric element band can detect change in the contact state with the end part of the conveyed sheet (change from contact state to noncontact state and change from noncontact state to contact state) with good accuracy and thus the side end position of the conveyed sheet can also be detected with good accuracy.
The first piezoelectric element band may be provided so as to make only one round around the axis of the roller like a spiral along the peripheral surface of the roller. According to the configuration, the appearance of the first piezoelectric element band becomes geometrically simple and thus it becomes easier to manufacture the first piezoelectric element (band sheet end detection device). The angle between the extension direction of the first piezoelectric element and the side end of the conveyed sheet, namely, the angle between the direction in which the first piezoelectric element extends when the peripheral surface of the roller is developed and the direction in which the side end of the conveyed sheet extends has an influence on the detection accuracy of the side end of the conveyed sheet. In contrast, as for the first piezoelectric element band provided like a spiral, the extension direction of the first piezoelectric element is roughly the same at any position in the axis direction of the roller. Therefore, the angle between the extension direction of the side end of any of various conveyed sheets different in size and the extension direction of the first piezoelectric element becomes roughly uniform, so that variation in the detection accuracy caused by the size difference of the conveyed sheet is suppressed and the side end position can be detected with stable accuracy.
The first piezoelectric element band may be formed so that a position opposed to the conveying passage of the conveyed sheet makes a transition from an outer portion of the contact area to an inner portion with rotation of the roller. According to the configuration, the first piezoelectric element band detects change from the noncontact state to the contact state with the conveyed sheet, whereby the side end position of the conveyed sheet can be detected.
The first piezoelectric element band may be formed so that a position opposed to the conveying passage of the conveyed sheet makes a transition from an inner portion of the contact area to an outer portion with rotation of the roller. According to the configuration, the first piezoelectric element band detects change from the contact state with the conveyed sheet to the noncontact state, whereby the side end position of the conveyed sheet can be detected.
The roller may have an outer peripheral dimension being a half or less of a conveying direction dimension of the conveyed sheet. According to the configuration, while the roller makes one revolution while the conveyed sheet is being conveyed in a state in which the roller and the conveyed sheet are in contact with each other, if the side end of the conveyed sheet does not come in contact with the first piezoelectric element band on the peripheral surface of the roller, the first piezoelectric element band and the side end of the conveyed sheet will come in contact with each other at the second revolution of the roller and thus the side end of the conveyed sheet can be detected reliably.
The first piezoelectric element band may be formed so that a position opposed to the conveying passage of the conveyed sheet makes a transition from an outer portion of the contact area to an inner portion and further to the outer portion with rotation of the roller. According to the configuration, the first piezoelectric element band detects change from the noncontact state to the contact state with the conveyed sheet or change from the contact state with the conveyed sheet to the noncontact state, whereby the side end position of the conveyed sheet can be detected.
The roller may have an outer peripheral dimension equal to or less than a conveying direction dimension of the conveyed sheet. According to the configuration, the first piezoelectric element band and the side end of the conveyed sheet reliably come in contact with each other during one revolution of the roller and the side end of the conveyed sheet can be detected.
The peripheral surface of the roller may contain metal and comes in contact with the back of the first piezoelectric element band to form one electrode and on the surface of the first piezoelectric element band, an opposite electrode is extended along the first piezoelectric element band. According to the configuration, the peripheral surface of the roller can be used as one electrode and one electrode need not be formed additionally.
An insulating cover may be provided so as to cover the first piezoelectric element band and the opposite electrode. According to the configuration, the first piezoelectric element band can be protected from contact with the conveyed sheet.
The roller may be provided on the peripheral surface with a second piezoelectric element band shaped like a band for detecting contact with the leading end of the conveyed sheet in a conveying direction thereof so as to make a round around the axis in a contact area with the conveyed sheet. According to the configuration, while the first piezoelectric element band detects the side end of the conveyed sheet, the second piezoelectric element band can detect the end part of the conveyed sheet in the conveying direction thereof (leading end).
That is, in an end position detection method of a conveyed sheet using the sheet end detection device described above, using the sheet end detection device, based on the phase of the roller indicated by the phase detection unit when the first piezoelectric element band detects change in a contact state with the conveyed sheet, the axis direction position of the roller is acquired about the change position of the contact state with the conveyed sheet, thereby detecting the end position in a direction orthogonal to the conveying direction of the conveyed sheet, and based on the phase of the roller indicated by the phase detection unit when the second piezoelectric element band detects change in the contact state with the conveyed sheet, the end position of the conveyed sheet in the conveying direction thereof is detected.
Accordingly, the positions of the side end and the leading end (and the trailing end as required) of the conveyed sheet can be detected with high accuracy. Moreover, each of the first piezoelectric element hand and the second piezoelectric element band can be formed without providing a considerable number of piezoelectric elements independent of each other, so that it is easy to manufacture the first and second piezoelectric elements (band sheet end detection device) and the cost can also be reduced.
An image recording apparatus according to the embodiment includes any of the sheet end detection devices described above and a recording head for ejecting ink to a recording sheet as the conveyed sheet to form an image.
According to the configuration, the side end position of the conveyed sheet can be detected with good accuracy. Thus, for example, to execute borderless printing of a photo, etc., the space area and the print area to be set can be roughly matched with each other, so that waste ink can be suppressed, peripheral ink contamination can be decreased, and image loss in the space surrounding can be suppressed.
According to the sheet end detection device of the embodiment, the image recording apparatus including the sheet end detection device, and the end position detection method of a recording sheet using the sheet end detection device described above, it is made possible to facilitate manufacturing and suppress the manufacturing cost while the end position (particularly, side end position) of a conveyed sheet such as a recording sheet is detected more precisely.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-310043 | Nov 2007 | JP | national |
