Patent Application
20110164102
1. Field of the Invention
The present invention relates to an image forming apparatus including a recording head for printing an image on a sheet such as a print sheet, and, more particularly to an image forming apparatus that has a feed tray.
2. Description of the Related Art
An image forming apparatus having a recording head includes, other than the recording head and an apparatus body having a sheet conveying mechanism, a feed tray for placing sheets such as print sheets and a discharge tray for discharging a sheet having an image formed thereon. For example, in an image forming apparatus described in JP-A-2006-142605, a feed tray is arranged in the rear part of an apparatus body and a discharge tray is arranged in the front part of the apparatus body.
When the feed tray is arranged in the rear part of the apparatus body as in the conventional image forming apparatus, the feed tray is in a position distant from an operator. Therefore, it is difficult for the operator to view sheets on the feed tray and perform work for supplying sheets to the feed tray. Moreover, it may be difficult to set sheets in an accurate position of the feed tray.
It is an object of the invention to provide an image forming apparatus and an image forming method with which it is possible to easily set sheets in a feed tray.
The invention provides an image forming apparatus that has an image forming unit including a recording head for printing an image on a sheet. The image forming apparatus includes a feed tray that is provided in the rear part of the image forming unit and on which the sheet is placed and a supporting mechanism on which the image forming unit is placed. The supporting mechanism includes a base member that has an upper surface, a turntable that is arranged on the base member and is movable along the upper surface of the base member, a guide section that guides the turntable to move from a first position to a second position further on a front side than the first position with respect to the base member, a rotation stopping mechanism that prevents the turntable from rotating when the turntable is in the first position, and a rotating mechanism that allows the turntable to rotate around an axis in an up-to-down direction in a state in which the turntable has moved to the second position.
In one aspect of the invention, the image forming apparatus includes a lock mechanism that can fix the turntable to the base member. Further, the image forming apparatus may include a control unit that permits printing when the lock mechanism is in a lock position and prohibits printing when the lock mechanism is in a lock release position.
Objects and advantages of the invention will become apparent from the description, which follows, or may be learned by practice of the invention.
The accompanying drawings illustrate embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain the principles of the invention.
An image forming apparatus according to an embodiment of the invention will be explained with reference to
The image forming unit 2 has a main body unit 11, a head housing unit 12 arranged on the main body unit 11, a first feed tray 13 arranged in a rear part of the main body unit 11, a discharge tray 14 arranged in a front part of the main body unit 11, a second feed tray 15 housed in a lower part of the main body unit 11, and the like.
A carriage 30, a carriage driving mechanism 31 for driving this carriage 30, a recording head 32 of an ink-jet system mounted on the carriage 30, and the like are arranged in the head housing unit 12. A replaceable ink cartridge (not shown) is housed in the recording head 32. As shown in
An example of the ink ejecting mechanism is a thermal type. The thermal type applies heat to the ink with a heater built in the recording head 32 to film-boil the ink. A pressure change is caused in the ink by growth or contraction of air bubbles due to this film boiling. An image is formed on the sheet S by ejecting the ink from the nozzle section 32a according to this pressure change. Other than the thermal type, for example, an ink ejecting mechanism that uses an element (e.g., a piezoelectric element) having a piezoelectric effect may be adopted. For example, the piezoelectric element is deformed by an electric current and an ink is ejected from a nozzle section according to a pumping action based on the deformation.
As shown in
The rotation of the motor 41 is transmitted to the carriage 30 via the timing belt 42. Therefore, the recording head 32 reciprocatingly moves along the carriage guide 40. The sensor unit 45 for controlling a position of the carriage 30 includes, for example, an encoder sensor 46 and a ladder plate 47 serving as a section to be detected. The ladder plate 47 extends in a direction parallel to the carriage guide 40. The ladder plate 47 has a ladder pattern formed at equal pitches. The ladder pattern of the ladder plate 47 is optically detected by the encoder sensor 46 according to the position of the carriage 30, whereby the position of the carriage 30 is detected. A signal of the position detected is inputted to a control unit 50 via a flexible harness 48.
The control unit 50 has a function of controlling a printing operation of the image forming apparatus 1 and includes, for example, a control circuit for controlling the sheet conveying mechanism 21, a control circuit for controlling the carriage driving mechanism 31, and a control circuit that manages an ink ejecting operation of the recording head 32.
As shown in
It is possible to place plural sheets (e.g., print sheets) on the first feed tray 13 stacking the sheets in the thickness direction. As shown in
The first conveying unit 61 includes a feed roller 70, a separation roller 71 located below the feed roller 70, and a separation unit 72 including a separation pad. The feed roller 70 feeds a sheet taken out from the lower end of the first feed tray 13 to the recording head 32. A torque limiter is provided in the separation roller 71.
The separation roller 71 rotates in a direction identical with a direction of rotation of the feed roller 70 according to a function of the torque limiter when only one sheet is present between the separation roller 71 and the feed roller 70. When two or more sheets are present between the feed roller 70 and the separation roller 71, the separation roller 71 rotates in a direction opposite to the direction of rotation of the feed roller 70. Therefore, when plural sheets are taken out from the first feed tray 13 and fed into a space between the feed roller 70 and the separation roller 71, an uppermost sheet and the other sheets are separated and only the uppermost sheet is fed to the recording head 32. A sheet separating mechanism for taking out sheets from the first feed tray 13 one by one is constituted by the feed roller 70, the separation roller 71, the separation unit 72, and the like.
The separation roller 71 is held by a holder 73. The holder 73 is movable in the up-to-down direction around a shaft 74 extending in the horizontal direction. The separation roller 71 is brought into contact with the feed roller 70 at a predetermined load and separated from the feed roller 70 by a not-shown cam. It is possible to move the separation unit 72 in a direction toward and away from the feed roller 70 with a not-shown cam.
After the sheet is fed, the separation roller 71 and the separation unit 72 are separated from the feed roller 70, moved to standby positions, and put on standby until the next sheet feed time, respectively. A return lever 75 is rotatably arranged near the lower end of the first feed tray 13. When the sheet taken out from the first feed tray 13 is conveyed to the feed roller 70, the return lever 75 is retracted by a spring to a position where the return lever 75 does not hinder the conveyance of the sheet. This return lever 75 rotates in synchronization with the movement of the separation roller 71 and the separation unit 72 to the standby positions and feeds a remaining sheet back to the first feed tray 13.
The first conveying unit 61 includes a conveying roller 80, a pinch roller 81 opposed to this conveying roller 80, a sheet sensor 82, a media sensor 83, and a switching member 84. The conveying roller 80 feeds a sheet to a space between the sheet guide member 22 and the recording head 32. The sheet sensor 82 has a sensor arm that is capable of detecting positions of the leading end and the trailing end of the sheet.
The media sensor 83 has a function of detecting a quality (e.g., paper quality) and thickness of a sheet. For example, when the surface of the sheet is made of a material having moisture-absorption characteristics, the media sensor 83 outputs a signal for increasing a quantity of ink ejected from the recording head 32 to the control unit 50. In the case of a sheet having glossiness on the surface thereof, for example, coat paper, the media sensor 83 performs control for outputting a signal for reducing a quantity of ink ejected from the recording head 32 to the control unit 50. In the case of color printing, a ratio of ejection of plural color elements may be adjusted on the basis of a signal from the media sensor 83.
As shown in
A sheet taken out from the first feed tray 13 by the feed roller 70 is conveyed to a space between the conveying roller 80 and the pinch roller 81 through the first conveying unit 61 as indicated by an arrow F1 in
The second conveying unit 62 includes rollers 100 and 101 for taking out a sheet from the second feed tray 15 of a cassette type, a switching member 102, guide members 103 and 104 for guiding the sheet taken out, a conveying roller 105 provided along the guide members 103 and 104, and a pinch roller 106 opposed to the conveying roller 105. The pinch roller 106 is pressed against the conveying roller 105 by a spring. It is possible to store plural sheets (e.g., print sheets) in the second feed tray 15 stacking the sheets in the thickness direction. The rollers 100 and 101 of the second conveying unit 62 function as sheet separating mechanisms for taking out sheets from the second feed tray 15 one by one.
A sheet taken out from the second feed tray 15 passes between the guide members 103 and 104 of the second conveying unit 62 through the switching member 102 as indicated by an arrow F2 in
The duplex-printing conveying unit 63 includes guide members 110 and 111, a conveying roller 112 provided along the guide members 110 and 111, and a pinch roller 113 opposed to the conveying roller 112. The pinch roller 113 is pressed against the conveying roller 112 by a spring. The guide members 110 and 111 are arranged between the switching member 84 of the first conveying unit 61 and the switching member 102 of the second conveying unit 62. At the time of duplex printing, a sheet is fed in an arrow F3 direction in
When duplex printing is performed, after an image is printed on one side of a sheet by the recording head 32, the trailing end of this sheet is detected by the sheet sensor 82. Immediately after the detection, the conveying roller 80 rotates reversely and a position of the switching member 84 is switched. Consequently, the sheet is sent to the duplex printing conveying unit 63 as indicated by the arrow F3 in
The discharging mechanism 64 has a discharge roller 120, a star wheel 121, a transmitting mechanism (not shown) for transmitting the rotation of the conveying roller 80 to the discharge roller 120 and the star wheel 121, and the like. The star wheel 121 is a wheel of a gear shape made of a thin plate of stainless steel or the like. A sheet having an image printed thereon by the recording head 32 is conveyed in a direction indicated by an arrow F4 to the discharge tray 14 while being pressed against the discharge roller 120 by the star wheel 121. The sheet after printing is prevented from floating from the discharge roller 120 by this start wheel 121.
As shown in
The head maintenance unit 24 shown in
It is possible to move the cap 141 in an up-to-down direction (an arrow D direction in
In the case of head maintenance, the recording head 32 is moved to a predetermined maintenance position by the carriage driving mechanism 31. Thereafter, the cap 141 is lifted to the recording head 32 by the cap driving unit 145 and the cap 141 comes into close contact with the recording head 32. The cap 141 covers the nozzle section 32a. Consequently, a remaining ink adhering to the nozzle section 32a is prevented from drying. In this state, the suction device 140 is actuated to generate a negative pressure on the inner side of the cap 141, whereby the remaining ink adhering to the nozzle section 32a is sucked. The waste ink sucked is discharged to a waste ink tank 147. Thereafter, the cap 141 moves away from the recording head 32 and the nozzle section 32a is cleaned by the blade member 142.
As shown in
The supporting mechanism 3 includes a base member 160 shown in
The movable unit 161 shown in
A guide section 190 is formed in the turntable 180. The guide section 190 includes a first guide 191 formed by a linear slit and a second guide 192 formed by an arcuate slit. The first guide 191 extends in a front-to-rear direction of the turntable 180. The second guide 192 is an arc with a midpoint P1 along a longitudinal direction of the first guide 191 as the center. The first guide 191 and the second guide 192 communicate with each other via a communicating section 193.
The movable unit 161 is movable in the front-to-rear direction of the base member 160 from a first position shown in
As shown in
As shown in
In other words, the turntable 180 can rotate in the horizontal plane around an axis X in the up-to-down direction shown in
The lock mechanism 182 has a lock member 200, a holder 201, a lock detection sensor 202, and the like. The lock member 200 can move in directions indicated by arrows Y1 and Y2 in
The lock detection sensor 202 has a function of detecting that the lock member 200 is in the lock position. When the lock state is detected by the lock detection sensor 202, a signal for permitting a printing operation of the image forming unit 2 is outputted to the control unit 50. An operation unit 203 is provided in the lock member 200. When the operation unit 203 is moved in the lock release direction (the arrow Y2 direction), the locking section 200a of the lock member 200 moves away from the first shaft 171, whereby the lock is released. This state is a lock release state. When the lock release state is detected by the lock detection sensor 202, a signal for prohibiting the printing operation of the image forming unit 2 is outputted to the control unit 50.
Operations of the image forming apparatus 1 including the supporting mechanism 3 will be hereinafter explained.
This image forming apparatus 1 is placed on a desk (not shown) or the like and used. When the image forming apparatus 1 is used, as shown in
Thus, a direction of the image forming unit 2 is changed. First, the operation unit 203 of the lock mechanism 182 is moved to the lock release position (the arrow Y2 direction shown in
When the lock by the locking mechanism 182 is released, the turntable 180 can move in the front-to-rear direction along the first guide 191. In this state, the turntable 180 is moved in an arrow Z direction to the second position shown in
When the turntable 180 moves to the second position as shown in
After the turntable 180 is moved to the second position, the turntable 180 is rotated, for example, in the clockwise direction around the first shaft 171. In this case, the turntable 180 rotates in the horizontal plane around the axis X in the up-to-down direction shown in
As shown in
After the sheet S is placed in the predetermined position of the feed tray 13, the turntable 180 is returned to the second position (
Under the standby state, a print start switch (not shown) is operated. Consequently, the sheet conveying mechanism 21, the carriage driving mechanism 31, and the like operate, an ink is ejected from the recording head 32 to the sheet S, and printing is performed. At the printing time, the image forming unit 2 is locked by the lock mechanisms 182. Therefore, the turntable 180 is prevented from moving at the printing time. It is possible to prevent irregularity of printing due to a shake of the image forming unit 2.
The lock mechanism 182 may lock the turntable 180 in a state in which the turntable 180 has rotated to the third position. The lock mechanism 182 may be able to lock the turntable 180 at a desired rotation position.
As explained above, the respective embodiments include the following steps:
moving the image forming unit 2 placed on the turntable 180 from the first position to the second position on the front side along the first guide 191 with respect to the base member 160;
moving the image forming unit 2 to the third position by rotating the image forming unit 2 around the axis X in the up-to-down direction in a state in which the image forming unit 2 has moved to the second position;
supplying the sheet S onto the feed tray 13 of the image forming unit 2 in a state in which the image forming unit 2 has moved to the third position;
locking the image forming unit 2 with the lock mechanism 182 not to move;
outputting a signal for permitting printing to the image forming unit 2 after the image forming unit is locked by the lock mechanism 182; and
forming an image on the sheet S with the recording head 32.
According to the embodiment, even if the feed tray 13 is provided in the rear part of the image forming unit 2, it is possible to bring the feed tray 13 close to the operator by rotating the image forming unit 2 when sheets are set. Therefore, it is possible to easily perform work for setting sheets in the feed tray 13.
The base member 160 and the movable unit 161 are not limited to the embodiment. For example, the lock mechanism 182 may perform lock and lock release of the turntable 180 with an electric actuator. It is possible to control the electric actuator with the control unit 50. When the turntable 180 is in the first position, the turntable 180 is fixed by moving the lock mechanism to the lock position with this actuator. In a state in which the turntable 180 is locked, it is possible to perform printing by the image forming unit 2.
It is also possible to implement the guide section 190 in various forms other than the embodiment. In short, the supporting mechanism 3 only has to include a guide section that guides the turntable 180 to move from the first position to the second position, a rotation stopping mechanism that prevents the turntable 180 from rotating when the turntable 180 is in the first position, and a rotating mechanism that allows the turntable to rotate in the horizontal plane in a state in which the turntable has moved to the second position.
It is also possible to apply the invention to an image forming apparatus for printing an image on sheets other than a print sheet, for example, sheets made of paper of various forms, cloth, plastics, and the like.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the invention as defined by the appended claims and equivalents thereof.
This application is a Continuation of application Ser. No. 11/619,724 filed Jan. 4, 2007, the entire contents of which are hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11619724 | Jan 2007 | US |
| Child | 13049010 | US |
