Heat source unit and erasing apparatus using the heat source unit

A heat source opening and closing mechanism, around a rotation shaft of which a plurality of spring members are wound, is opened and closed an outside unit including a first heating member and a second press roller against an inside unit including a second heating member and a first press roller. The heat source opening and closing mechanism is opened and closed among a closed position where the first press roller faces to the first heating member and the second press roller faces to the second heating member, a first open state in which the load by the outside unit is commensurate with a first elastic force of the spring member, and a second open state in which an opening angle is larger than that in the first open state.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2013-093753, filed Apr. 26, 2013, the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate to a heat source unit and an erasing apparatus which uses the heat source unit.

BACKGROUND

Conventionally, in an image forming apparatus which heats and presses the toner on an electronic photograph and the like to fix the toner on the paper, as a method for removing papers jammed in a fixing apparatus or papers stopping when passing through the fixing apparatus, a method of rotating a conveyance rib contacting with a press roller and a heat roller, or a method of releasing the pressure between the press roller and the heat roller is widely used to draw the papers out.

DETAILED DESCRIPTION

In accordance with one embodiment, a heat source unit comprises a first heating member configured at one side of a paper at the upstream side of a paper conveyance direction to heat the paper from the one side; a first press roller configured opposite to the first heating member to press the paper from the other side against the first heating member, and meanwhile rotate to convey the paper in the conveyance direction; a second heating member configured at the other side of the paper at the downstream side of the first press roller in the paper conveyance direction to heat the paper from the other side; a second press roller configured opposite to the second heating member to press the paper from the one side against the second heating member, and meanwhile rotate to convey the paper in the conveyance direction; and a heat source opening and closing mechanism, around a rotation shaft of which a plurality of spring members are wound, configured to be opened and closed by rotating an outside unit including the first heating member and the second press roller against an inside unit including the second heating member and the first press roller; wherein the heat source opening and closing mechanism is opened and closed among a closed position where the first press roller faces to the first heating member and the second press roller faces to the second heating member, a first open state in which the load by the outside unit is commensurate with a first elastic force of the spring member, and a second open state in which an opening angle is larger than that in the first open state, and the combination force of the load by the outside unit and a pressure force applied in the first open state in the open direction of the heat source is commensurate with a second elastic force of the spring member.

Hereinafter, the embodiment is described in detail with reference to the accompanying drawings.

FIG. 1is a schematic view illustrating an example of an entire constitution of an erasing apparatus10to which a heat source unit according to the present embodiment is applied. The erasing apparatus10comprises an operation panel11including operation buttons and a display section, a paper feed section12, a scanner13serving as a reading section, a ultrasonic sensor14for detecting the conveyance state of paper S and an erasing section20serving as a heat source unit for erasing an image on the paper S. In addition to a first conveyance path141, a second conveyance path142, a third conveyance path143, a fourth conveyance path144and a fifth conveyance path145, the erasing apparatus10further comprises a first paper discharge tray15and a second paper discharge tray (reject box)16serving as paper discharge sections.

Each of the conveyance paths141˜145is provided with a plurality of conveyance rollers17to convey the paper S, and a plurality of motors18to drive each conveyance roller17. Further, each of the conveyance paths141˜145is provided with a plurality of gates19to correctly convey the paper S to each of the conveyance paths141˜145.

The first conveyance path141conveys the paper S from the paper feed section12to the scanner13. The second conveyance path142conveys the paper S from the scanner13to the erasing section20along a direction indicated by an arrow A. The third conveyance path143conveys the paper S from the erasing section20to the scanner13again. The fourth conveyance path144conveys the paper S from the scanner13to the first paper discharge tray15. The fifth conveyance path145conveys the paper S from the scanner13to the second paper discharge tray (reject box)16.

The first paper discharge tray15collects, for example, a reusable paper S the image on which is erased. The second paper discharge tray (reject box)16collects a not-reusable paper S which is generally scraped and recycled.

The erasing apparatus10mainly carries out the following operations (1)-(5):

(1) reading the paper S fed from the paper feed section12by the first conveyance path141using the scanner13. The scanner13includes a first scanner131and a second scanner132to read two sides of the paper S. The scanner13reads, for example, image data before the image on the paper S is erased. Simultaneously, the scanner13reads the printing state of the paper S.

(2) storing the image data read by the scanner13. Further, according to the printing state of the paper S read by the scanner13, if the paper S is ripped or crumpled, the paper S is guided to the fifth conveyance path145and then conveyed to the reject box16. The paper S without any rip or crumple is conveyed to the erasing section20by the second conveyance path142.

(3) heating the paper S conveyed to the erasing section20when the paper S passes through the erasing section20to erase the image formed on the paper S by heating. The erasing section20heats and presses the paper S at a relatively high temperature of, for example, 180˜200 degrees centigrade, to erase the image on the paper S. The detailed constitution of the erasing section20is described later.

(4) conveying the paper S passing through the erasing section20to the scanner13again by the third conveyance path143. The scanner13reads the printing state of the paper S again to confirm whether or not the image formed with erasable coloring agent in an image area is actually erased.

(5) conveying the reusable paper S to the first paper discharge tray15by the fourth conveyance path144. According to the printing state of the paper S read by the scanner13, if there is an image formed with inerasable coloring agent or a handwritten image left in the image area of the paper S, or if the paper S is ripped or crumpled, the paper S is conveyed to the reject box16by the fifth conveyance path145.

FIG. 2is a cross-sectional view illustrating a concrete example of the internal structure of the erasing section20. The erasing section20conveys the paper S on the conveyance path, while heating the paper S fed by the paper feed section12with a heat source at a given heat source setting temperature, so as to erase the image on the paper S. As shown inFIG. 2, the erasing section20has a first erasing section201and a second erasing section202. The first erasing section201includes a first heat roller213serving as a heating member and a first press roller301serving as a pressing member. Similarly, the second erasing section202includes a second heat roller214and a second press roller302. Though the first erasing section201is structurally identical to the second erasing section202, the arrangement positions of the heat rollers and the press rollers are reversed in a vertical direction. The first press roller301and the second press roller302are cylindrical rotation rollers which extend in a width direction of the paper S and rotate around rotation axes303and304, respectively.

The paper S is conveyed on the second conveyance path142from a direction indicated by an arrow A. The direction indicated by the arrow A is equivalent to the direction indicated by the arrow A inFIG. 1. The first heat roller213and the second heat roller214are respectively provided with cylindrical halogen heaters241and242. A paper guide31is arranged at a paper conveying-in side and a paper guide32is arranged at a paper conveying-out side. The paper guide31guides the conveying-in of the paper S together with a paper guide33. The paper guide33is fixed in the erasing apparatus10opposite to the paper guide31. The paper guide32guides the conveying-out of the paper S together with a paper guide34. The paper guide34is fixed in the erasing apparatus10opposite to the paper guide32. The paper guides32and34guide the conveyance of the paper S in the second erasing section202.

The first press roller301and the second press roller302are cylindrical rotation rollers which are respectively contacted with the first heat roller213and the second heat roller214in a longitudinal direction thereof, and rotate around the rotation axes303and304, respectively. The first press roller301and the second press roller302are formed by, for example, contacting a tube having mold releasability with the surface of an elastic body such as a silicon sponge and the like. The rotation axes303and304are energized in the directions of the first heat roller213and the second heat roller214, respectively, thereby clamping, pressing and heating the paper S between the first heat roller213and the first press roller301, and then between the second heat roller214and the second press roller302, while conveying the paper S.

A pressure (pinch pressure) for energizing the first press roller301towards the direction of the first heat roller213in the first erasing section201is indicated by F1. A pressure (pinch pressure) for energizing the second press roller302towards the direction of the second heat roller214in the second erasing section202is indicated by F2. The ratio of the pinch pressure F1 to the pinch pressure F2 is, for example, 3:2.

For example, the rotation shaft303is pulled by a spring towards the side of the first heat roller213due to the application of the pinch pressure F1. Further, for example, the rotation shaft304is pulled by a spring towards the side of the second heat roller214due to the application of the pinch pressure F2.

An erasing processing carried out on the paper S by the first erasing section201and the second erasing section202is described below. The paper S is guided by the paper guides31and33, and conveyed to the erasing section20through the second conveyance path142. The press roller301of the first erasing section201and the press roller302of the second erasing section202are rotated in opposite directions, thereby conveying the paper S in the direction indicated by the arrow A at a preset speed.

The first press roller301is pressed against and contacted with the first heat roller213through the pinch pressure F1 in the first erasing section201at the upstream side of the conveyance path. A contact point (one dotted lines X01) of the first press roller301and the first heat roller213forms a nip area where heat is transferred to the paper S, and the surface of the paper is heated and the image formed on one side of the paper S is erased by conveying the paper S through the nip area X01.

In a case where the image is formed on the paper S with erasable coloring agent, the coloring agent is erased at a certain temperature. The first heat roller213is uniformly heated by a cylindrical halogen heater241and maintained at an erasing temperature. The temperature of the first heat roller213is detected by a thermistor (not shown), and the first heat roller213is maintained at a proper temperature based on the result of the temperature detection.

The paper S, after being discharged from the first erasing section201, is guided by the paper guides32and34, and conveyed into the second erasing section202. In the second erasing section202at the downstream side of the conveyance path, the position relation of the second press roller302and the second heat roller214is opposite to that in the first erasing section201in the vertical direction, and the second press roller302is pressed against and contacted with the second heat roller214through the pinch pressure F2.

A contact point (one dotted lines X02) of the second press roller302and the second heat roller214forms a nip area where heat is transferred to the paper S. The surface of the paper is heated and the image formed on the other side of the paper S is erased by conveying the paper S through the nip area X02. The paper S both sides of which are color erased is discharged along the paper guide34, and then conveyed to the third conveyance path143.

Though the first erasing section201is structurally identical to the second erasing section202, the arrangement position of the heat roller and press roller in the first erasing section201is opposite to that in the second erasing section202, and each roller is arranged in series, therefore, the image formed on one side of the paper S is erased by the first erasing section201, and the image formed on the other side of the paper S is erased by the second erasing section202. Thus, the image formed on two sides of the paper S can be erased efficiently.

FIG. 3is an oblique view illustrating the erasing section20shown inFIG. 2. As shown inFIG. 3, a pair of opening and closing levers20ais arranged at two ends of the erasing section20. A pair of felts20bserving as insulation material is respectively attached near the fulcrums of the pair of opening and closing levers20aon the side of the erasing section20. Further, a pair of handles20cis arranged below the pair of felts20bfor an operator to use when opening the erasing section20. The surface of the pair of handles20cis covered with insulation material. The direction indicated by an arrow B represents the conveyance direction of the paper S.

FIG. 4is an oblique view illustrating a state in which the engagement of a hook portion20dof the opening and closing lever20aof the erasing section20shown inFIG. 3with a rotation shaft is released, andFIG. 5is an enlarged oblique view illustrating the main portions ofFIG. 4. As shown inFIG. 4, the pair of opening and closing levers20acan be pressed downwards (a direction indicated by an arrow inFIG. 4). At this time, as shown inFIG. 5, if the connection of the hook portion20dformed in a hook shape at the other end of the pair of opening and closing levers20awith a lock shaft20eis released, the erasing section20(heat source unit), which is fixed in a closed state at a contact position where the first press roller301contacts with the first heat roller213and the second press roller302contacts with the second heat roller214, can be opened. The contact position is, in other words, a state in which the first press roller301is opposite to the first heat roller213and the second press roller302is opposite to the second heat roller214, and in which the paper can be conveyed.

FIG. 6andFIG. 7are oblique views respectively illustrating an open state of a first stage in the erasing section20shown inFIG. 3.FIG. 6is a diagram viewed from the side of an open port of the heat source, on the contrary,FIG. 7is a diagram viewed from the side of a torsion spring20g. When the connection of the hook portion20dof the opening and closing lever20awith the lock shaft20eis released, in the heat source opening and closing mechanism of the erasing section20, an outside unit U2 including the first heat roller213and the second press roller302rotates around a rotation shaft20fagainst an inside unit U1 including the second heat roller214and the first press roller301, thereby opening the heat source opening and closing mechanism. Further, as shown inFIG. 7, in the heat source opening and closing mechanism of the erasing section20, a plurality of torsion springs20gare wound around the rotation shaft20f, and the elastic force of the torsion springs20gacts in a closing direction. Therefore, the heat source opening and closing mechanism of the erasing section20rotates around the rotation shaft20funtil it reaches the first open state in which the load (own weight) by the outside unit U2 is commensurate with the first elastic force of the torsion spring20g. It is preferred to select and adjust the torsion spring20ghaving such an elastic modulus that an opening angle θ1of the heat source opening and closing mechanism in the first open state can be kept at, for example, about 60 degrees. In the present embodiment, compared with a coil spring, the torsion spring20ghas an advantage in strong elastic force generated when pressed by the same weight and an advantage in light weight, thus, the torsion spring20gis used as the spring member, however, other spring such as the coil spring may also be used. Further, the number of the torsion spring20gis not limited.

FIG. 8andFIG. 9are an oblique view and a side view respectively illustrating an open state of a second stage in the erasing section20shown inFIG. 3.FIG. 10is an oblique view viewed (contrary toFIG. 8) from the side of the torsion spring20g. In the open state of the first stage shown inFIG. 6andFIG. 7, if the operator further presses the outside unit U2, the heat source opening and closing mechanism of the erasing section20further rotates around the rotation shaft20funtil it reaches the second open state in which an opening angle θ2is larger than the opening angle θ1in the first open state, and the combination force of the load (own weight) by the outside unit U2 and the pressure force applied by the operator in the first open state in the open direction of the heat source is commensurate with the second elastic force of the torsion spring20g. The maximum value of the opening angle θ2is determined according to the range of the motion of the outside unit U2 away from the inside unit U1, and is preferred to be, for example, about 90 degrees. In the second open state, if the operator lets go of the hand, the outside unit U2 is rotated around the rotation shaft20fby the elastic force in the closing direction until it reaches the first open state. Then, in the first open state, for example, if the operator puts thumbs under the pair of handles20cand presses the pair of felts20bwith index fingers to apply a force to the outside unit U2 in the closing direction, the outside unit U2 rotates around the rotation shaft20ftowards the direction of the inside unit U1, and the opening and closing lever20ais pushed up by interlocking with this, and the hook portion20dis connected with the lock shaft20e, thereby, the outside unit U2 returns to the closed state shown inFIG. 3.

In this way, the heat source opening and closing mechanism which separates the heat rollers213,214and the press rollers301,302to remove the paper S jammed in the heat source unit or the paper S stopping in the heat source unit is adopted in the erasing apparatus10in which the heat source unit according to the present embodiment is applied. The heat source opening and closing mechanism has such a structure that the heat rollers213,214and the press rollers301,302in the heat source unit can be separated by taking the rotation shaft20fas a center, and when opening the heat source unit, the heat source unit is opened to a certain angle θ1 first due to the action of the torsion spring20garranged around the rotation shaft20f, and is opened to a larger angle if being further pressed. The papers stopping in the heat source unit can be pulled out without any obstruction by opening the heat source unit to a certain angle θ1 first. Next, the paper jammed in the heat source unit can be removed easily by further pressing the heat source unit and opening the heat source unit to a larger angle. That is, with such a structure that the heat source unit is opened in stages, the risk that the operator contacts with the heat source having a high temperature in the paper removing operation can be greatly reduced.

Further, in the embodiment described above, it is exemplified the heat source unit is applied to the heat source unit of the erasing apparatus10; however, the present invention is not limited to this. For example, the heat source unit may also be applied to the heat source unit of a fixing apparatus. In addition, in the present embodiment, the heat rollers213and214are described as heating members, however, heat plates may also be used.