Patent Application
20150197112
Embodiments described herein relate generally to a heating device for use with an erasing apparatus.
An erasing apparatus performs an erasing processing on a sheet having an image by applying heat and pressure to the image. Such an erasing apparatus employs a heat roll-type heating method, in which a pair of rollers rotates while being heated. By passing through a contact portion of the rollers, the image on the sheet is heated and erased. In the erasing apparatus employing the heat roll-type heating method, a nip area is secured by urging one of the rollers towards the other one of the rollers, and a heat of the roller is transferred to the sheet.
In addition, there are some erasing apparatuses that employ two pairs of heating units, each having a heat roller and a press roller. In such an erasing apparatus, the first heating unit performs an erasing processing on one surface of the sheet and the second heating unit performs an erasing processing on the other surface of the sheet, so that both surfaces of the sheet may be erased during one-time sheet conveyance through the erasing apparatus.
In this type of erasing apparatus, if a sheet j am occurs at any of the heating units, a user pulls out the sheet by opening the erasing apparatus. In order to facilitate clearing of jams, the erasing apparatus employs a heating device opening and closing mechanism that causes the first heating unit and the second heating unit to be opened at the same time using a common rotating shaft as a rotational axis.
However, such a heating device opening and closing mechanism has a drawback in that it is difficult to optimize pressures applied in both of the first and second heating units because the pressure in the first heating unit is associated with the pressure in the second heating unit. In particular, the pressure in the second heating unit, which is disposed far from the rotating shaft, varies depending on sizes of members holding the heat roller or the press roller by a greater amount relative to the first heating unit.
A heating device includes a first heating roller configured to heat a first surface of a sheet, a second heating roller configured to heat a second surface of the sheet, the second heating roller disposed downstream in a sheet conveying direction with respect to the first heating roller, a first pressing roller configured to press the sheet against the first heating roller, the first pressing roller and the second heating roller forming a first unit, a second pressing roller configured to press the sheet against the second heating roller, the second pressing roller and the first heating roller forming a second unit that is rotatable about a rotational axis relative to the first unit, an eccentric shaft unit disposed on one of the first unit and the second unit and extending in a direction parallel to the rotational axis, a rotational position of an eccentric portion of the eccentric shaft unit being changeable, and an engaging unit disposed on the other one of the first unit and the second unit, and configured to engage with the eccentric shaft, a position of the second unit relative to the first unit being adjusted when the rotational position of the eccentric portion of the eccentric shaft unit is changed.
Hereinafter, description will be given with regard to embodiments in detail using drawings.
As illustrated in
Along conveyance paths 141-145, a plurality of conveying rollers 17 to convey the sheet S are disposed, and a plurality of motors 18 are disposed to drive respective conveying rollers 17. In addition, the respective conveyance paths 141-145 are provided with a plurality of gates 19 in order to accurately convey the sheet S to the respective conveyance paths 141-145.
Along the first conveyance path 141, the sheet S is conveyed from the sheet feeding unit 12 to the scanner 13. Along the second conveyance path 142, the sheet S is conveyed from the scanner 13 to the heating device 20 in a direction indicated by an arrow A. Along the third conveyance path 143, the sheet S is conveyed from the heating device 20 to the scanner 13 again. Along the fourth conveyance path 144, the sheet S is conveyed from the scanner 13 to the first sheet ejecting tray 15. Along the fifth conveyance path 145, the sheet S is conveyed from the scanner 13 to the second sheet ejecting tray (reject box) 16.
The first sheet ejecting tray 15 stores a sheet S which can be reused, for example, after an image erasing processing. The second sheet ejecting tray (reject box) 16 stores a sheet S which cannot be reused and is recycled with normal disposal.
The erasing apparatus 10 generally performs the following operations (1) to (5).
(1) The sheet S fed from the sheet feeding unit 12 through the first conveyance path 141 is scanned by the scanner 13. The scanner 13 includes a first scanner 131 and a second scanner 132 and scans both surfaces of the sheet S. The scanner 13 reads out image data, for example, before an image of the sheet S is erased. At the same time, a printing status of the sheet S is determined based on the image data.
(2) Saving or the like of the image data read out by the scanner 13 is performed. If there is a wrinkle or a tear on the sheet S in view of the printing status acquired with the scanner 13, the sheet S is guided to the fifth conveyance path 145 and is conveyed to the reject box 16. The sheet S without any wrinkle or tear is conveyed to the heating device 20 through the second conveyance path 142.
(3) The sheet S conveyed to the heating device 20 is heated when passing through the heating device 20, an image formed on the sheet S is erased by heat. The heating device 20 erases the image on the sheet S by pressurizing and heating the sheet S, for example, at a relatively high temperature of 180° C. to 200° C. Description with regard to a specific configuration of the heating device 20 will be given below.
(4) The sheet S which has passed through the heating device 20 is conveyed to the scanner 13 again through the third conveyance path 143. The printing status is determined again based on the image scanned by the scanner 13 in order to confirm whether or not the image formed with a erasable color agent in an image area is surely erased.
(5) The sheet S which can be reused is conveyed to the first sheet ejecting tray 15 through the fourth conveyance path 144. If an image formed with a non-erasable color agent or an handwritten image remains in the image area, or an wrinkle or a tear occurs in view of the printing status acquired with the scanner 13, the sheet S is conveyed to the reject box 16 through the fifth conveyance path 145.
The heating device 20 conveys the sheet S fed by the sheet feeding unit 12 through the conveyance path while heating the sheet S with a heat source having a predetermined temperature and erases the image on the sheet S. As illustrated in FIG. 2, the heating device 20 includes a heat source in each of a first erasing unit 201 and a second erasing unit 202. The first erasing unit 201 (first heat source) includes a first heat roller 213, which is a heating member, and a second press roller 301, which is a pressing member. In the same manner, the second erasing unit 202 (second heat source) includes a second heat roller 214 and a second press roller 302. In addition, the first erasing unit 201 and the second erasing unit 202 have substantially the same configurations, but the first erasing unit 201 and the second erasing unit 202 are flipped upside down. The first press roller 301 and the second press roller 302 are rotating rollers which respectively rotate around rotating shafts 303 and 304 and formed in a cylindrical shape which extends in a width direction of the sheet S.
The sheet S is conveyed along the second conveyance path 142 from the direction of the arrow A. The direction of the arrow A corresponds to the direction of the arrow A of
The first press roller 301 and the second press roller 302 are cylindrical rotating rollers which are respectively in contact with the first heat roller 213 and the second heat roller 214 in a longitudinal direction and respectively rotate around the rotating shafts 303 and 304. The first press roller 301 and the second press roller 302, for example, are formed by adhering a tube having a releasing property on a surface of an elastic body such as silicone sponge and the like. The sheet S is interposed between the first heat roller 213 and the first press roller 301 and between the second heat roller 214 and the second press roller 302 and is conveyed while being pressurized and heated by respectively urging the rotating shafts 303 and 304 towards the first heat roller 213 and the second heat roller 214.
A pressure (pinch pressure) which urges the first press roller 301 towards the first heat roller 213 is indicated as F1 in the first erasing unit 201. A pressure (pinch pressure) which urges the second press roller 302 towards the second heat roller 214 is indicated as F2 in the second erasing unit 202. A ratio of the pinch pressure F1 and the pinch pressure F2 is, for example, 3:2.
For example, the rotating shaft 303 is pulled to the first heat roller 213 by a spring in order to cause the pinch pressure F1. In addition, for example, the rotating shaft 304 is pulled to the second heat roller 214 by a spring in order to cause the pinch pressure F2.
Next, description will be given with regard to the erasing processing on the sheet S by the first erasing unit 201 and the second erasing unit 202. The sheet S is guided by the sheet guides 31 and 33 along the second conveyance path 142 and then is conveyed into the heating device 20. The sheet S is conveyed in the direction of the arrow A at a preset rate by the press roller 301 of the first erasing unit 201 and the press roller 302 of the second erasing unit 202 rotating in an opposite direction to each other.
The first press roller 301 is urged towards the first heat roller 213 and is brought into contact with the first heat roller 213 with the pinch pressure F1 in the first erasing unit 201 upstream of the conveyance path with respect to the second erasing unit 202. A nip area is formed at a contact region (chain line X01) of the first press roller 301 and the first heat roller 213, where heat is transferred to the sheet S. A sheet surface is heated while the sheet passes through the nip area X01, and then the image formed on one surface of the sheet S is erased.
If the image is formed on the sheet S with a erasable color agent, the color agent is decolorized when it reaches a predetermined temperature. The first heat roller 213 is uniformly heated by the cylindrical halogen heater 241 and is maintained at an erasable temperature. The temperature of the first heat roller 213 is detected by a thermistor (not illustrated) and is maintained at an appropriate temperature based on the detected temperature.
After the sheet S is ejected from the first erasing unit 201, the sheet S is guided by the sheet guides 32 and 34 and is conveyed into the second erasing unit 202. Top and bottom relation of the second press roller 302 and the second heat roller 214 is inverted from the first erasing unit 201, and the second press roller 302 is urged towards the second heat roller 214 and brought into contact with the second heat roller with the pinch pressure F2 in the second erasing unit 202 disposed downstream of the conveyance path with respect to the first erasing unit 201.
A nip area is formed in a contact region (chain line X02) of the second press roller 302 and the second heat roller 214, where heat is transferred to the sheet S. A sheet surface is heated while the sheet S passes through the nip area X02, and the image formed on the other surface of the sheet S is erased. The sheet S of which images on both surfaces are erased is ejected along the sheet guide 34, and is conveyed towards the third conveyance path 143.
The configurations of the first erasing unit 201 and the second erasing unit 202 are substantially the same. However, since the erasing units are flipped upside down and respective rollers are disposed in series state, one surface of the sheet S is erased by the first erasing unit 201 and the other surface of the sheet S is erased by the second erasing unit 202. Therefore, it is possible to effectively erase both sides of the sheet S.
In addition, though details will be described later, the heating device 20 of the present embodiment is configured to be divisible into two units with respect to a conveying path of the sheet as a border. When the heating device 20 is built into the erasing apparatus 10, the first press roller 301 and the second heat roller 214 are included in an inside unit U1 positioned inside. In addition, the first heat roller 213 and the second press roller 302 are included in an outside unit U2 positioned outside.
As illustrated in
Next, description will be given with regard to a nip width adjustment structure in the above-described heating device 20. As illustrated in
If the operating portion 21a rotates counterclockwise from the engaged state illustrated in
On the other hand, if the operating portion 21a is rotated clockwise from the engaged state illustrated in
Here, the opening and closing lever 21 is fixed in the following steps of (1) to (4).
(1) The eccentric shaft 22 is positioned in an appropriate position.
(2) After the eccentric shaft 22 is positioned, the eccentric shaft is fixed by a fixing screw 22a in its center. Specifically, a groove (not illustrated) in which a flathead screw driver or the like can be inserted is formed on the eccentric shaft 22 in advance, the eccentric shaft 22 can be positioned in a desired position by the operator fixing the fixing screw 22a in the groove.
(3) After the eccentric shaft 22 is fixed by the fixing screw 22a, the position of the eccentric shaft 22 is fixed.
(4) Since the fixed eccentric shaft 22 does not rotate, the engagement of the hook portion 21b with the eccentric shaft 22 is also fixed.
Therefore, in the heating device 20 according to the present embodiment, it is possible to adjust a fixing position of the outside unit U2 including the second press roller 302 by operating the opening and closing lever 21 which is placed on both left and right ends of the heating device 21. That is, it is possible to adjust the nip width of the second erasing unit 202 by adjusting a pressure of the second press roller 302 independently on both the left and right ends. In addition, since the opening and closing lever 21 and the eccentric shaft 22 are disposed on the outside of a heat source cover covering an end portion of the second heat roller 214, it is possible to simply adjust the nip width from the outside of the heating device without removing the heat source cover. The nip width of the second press roller contained in the outside heat source (second erasing unit 202) has a great impact on occurrence of wrinkles. However, it is possible to suppress the occurrence of wrinkles by adjusting the nip width as described above.
Hereinafter, description will be given with regard to a heating device 20 according to a second embodiment. Since reference numerals in common with the reference numerals in the first embodiment indicate the same subjects, the points which are different from the first embodiment will be described in detail.
As illustrated in
As illustrated in
When a lower end of the pressure member frame 28 is pulled by a pressure spring 29 for a second heat source, the pressure member frame 28 is rotated around the rotating shaft 27, and a pressure is applied to the second heat roller 214 by the second press roller 302.
If it is desired to increase the pressure applied by the second press roller 302 compared to a state illustrated in
Conversely, if it is desired to decrease the pressure applied by the second press roller 302 compared to a state illustrated in
Therefore, according to the heating device 20 according to the present embodiment, since the first nip width adjustment member 26 is provided on both left and right ends of the second press roller 302, it is possible to optimize the nip width by independently adjusting the pressure applied by the second press roller 302 on both left and right ends without removing the pressure spring 29.
Hereinafter, description will be given with regard to a heating device 20 according to a third embodiment.
The heating device 20 illustrated in
As illustrated in
If it is desired to increase a pressure applied by the first press roller 301 compared to a state illustrated in
Conversely, if it is desired to decrease the pressure applied by the first press roller 301, the plate 36a is rotated counterclockwise (arrow L direction) around the adjustment member rotating shaft 36d. Since the rotating shaft 37 of the pressure member frame 38 slides along the first slit hole 36b and the first press roller 301 is separated from the first heat roller 213, the pressure applied by the first press roller 301 is decreased and the nip width is decreased. After completion of the adjustment, the position of the plate 36a is fixed by the screw 361 being tightened in the fixing slit hole 36c.
In this manner, it is possible to independently adjust a nip width of the first heat source as well as the second heat source on both the left and right ends by providing the second nip width adjustment members 36 at the first heat source side.
In the above-described embodiments, the nip width is manually adjusted. In addition, a configuration with a mechanically-driven adjustment also conceivable. A gear train 26e is formed on one end of the first nip width adjustment member 26 of the heating device 20 illustrated in
If it is desired to increase a pressure applied by the second press roller 302, the plate 26a is rotated clockwise around the adjustment member rotating shaft 26d by the driving device 40 driving the gear 401 to rotate counterclockwise. Conversely, if it is desired to decrease the pressure applied by the second press roller 302, the plate 26a is rotated counterclockwise around the adjustment member rotating shaft 26d by the driving device 40 driving the gear 401 to rotate clockwise. In this manner, it is possible to mechanically adjust the nip width by driving the first nip width adjustment member 26 using the driving device 40. The heating device 20 is incorporated into the erasing apparatus 10 in
In addition, it is possible to apply the structure of the nip width adjustment in the above-described heating device 20 to a fixing device incorporated into an image forming apparatus that employs an electrophotographic process, such as a copying machine, a facsimile, and a printer. In general, a fixing device has a pair of rollers including a heat roller and a press roller, conveys one sheet into a nip formed between the pair of rollers, pressurizes a toner image onto the sheet while heating the toner image, and fixes the toner onto the sheet. Therefore, if the fixing device includes a heating device opening and closing mechanism between the heat roller and the press roller, it is possible to easily perform the adjustment of the nip width by applying a connection structure of the opening and closing lever 21 and the eccentric shaft 22, which are described in the first embodiment, to the heating device opening and closing mechanism. In the same manner, it is possible to provide the nip width adjustment member 26 described in the second embodiment on the end portion of the press roller of the fixing device.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein maybe made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
