Sheet processing device and sheet manufacturing apparatus

Provided are a sheet processing device and a sheet manufacturing apparatus capable of removing color material from printed parts without excess or deficiency. A sheet processing device has a detector configured to detect a printed part printed on a sheet; and an eraser configured to selectively remove at least a surface part of a printed area including the printed part detected by the detector. The eraser includes a grinding tool to grind the sheet, and a pressure mechanism configured to selectively increase contact pressure between the sheet and the grinding tool in the printed area.

BACKGROUND

1. Technical Field

The present invention relates to a sheet processing device and a sheet manufacturing apparatus.

2. Related Art

With increased concern about the environment, interest in both reducing consumption of paper and recycling paper has grown. See, for example, JP-A-2014-178514.

JP-A-2014-178514 describes an image erasing device that has a recording medium conveyance mechanism for holding and conveying a recording medium on which an image is recorded, and a recording medium erasing mechanism that is disposed to the recording medium conveyance path and erases the front and back sides of the recording medium to the extent that the image recorded on the recording medium is removed. The recording medium erasing mechanism has erasing members (rollers with a coarse surface) that contact both sides of the recording medium conveyed by the recording medium conveyance mechanism.

However, because the recording medium erasing mechanism described in JP-A-2014-178514 grinds the entire surface of the recording medium, even the white parts of the recording medium where nothing is recorded are also ground. As a result, depending on how much is ground, reusing the recording medium may not be possible.

SUMMARY

An object of the several embodiments of the present invention is to provide a sheet processing device and a sheet manufacturing apparatus capable of removing color material from the printed parts without excess or deficiency.

The present invention is directed to solving at least part of the foregoing problem, and may be embodied as described below.

A sheet processing device according to one aspect of the invention has a detector configured to detect a printed part printed on a sheet; and an eraser configured to selectively remove at least a surface part of a printed area including the printed part detected by the detector.

This configuration enables selectively removing at least the surface part of the printed area. More specifically, while removing the printed area, wasteful removal of material outside the printed area can be prevented. In other words, the printed part can be removed without excess or deficiency.

Preferably in a sheet processing device according to another aspect of the invention, the eraser includes a grinding tool to grind the sheet, and a pressure mechanism configured to selectively increase in the printed area contact pressure between the sheet and the grinding tool.

This configuration enables selectively removing the printed area of the sheet.

Further preferably in a sheet processing device according to another aspect of the invention, the pressure mechanism has a pressure member disposed movably to and away from the grinding tool, and directly or indirectly applies pressure to the sheet from the opposite side of the sheet as the grinding tool.

This configuration enables pressing and grinding the printed area of the sheet against the grinding tool.

In a sheet processing device according to another aspect of the invention, a conveyor is configured to convey the sheet by a conveyor belt at least between the detector and the eraser; and the pressure member presses the sheet to the grinding tool through the conveyor belt.

This configuration can prevent the pressure member applying excessive pressure to the sheet. Unintentionally damaging the sheet can therefore also be prevented.

Further preferably in a sheet processing device according to another aspect of the invention, the pressure member has multiple pressure elements, and selectively drives the pressure elements to increase contact pressure of the grinding tool to the sheet in parts.

This configuration can more reliably prevent grinding parts outside the printed area.

Further preferably in a sheet processing device according to another aspect of the invention, the multiple pressure elements are disposed in a direction intersecting the conveyance direction of the sheet in the eraser.

This configuration can push the printed area to the grinding tool and remove the printed area regardless of where the printed area is located on the sheet.

Further preferably in a sheet processing device according to another aspect of the invention, the pressure elements are rollers or pins.

This configuration enables reducing the size of the pressure elements, and disposing a relatively large greater number of pressure elements. As a result, even relatively small printed areas can be precisely removed.

Further preferably in a sheet processing device according to another aspect of the invention, the pressure member presses and deforms the sheet to protrude in the printed area before the grinding tool grinds the printed area.

This configuration can more effectively prevent grinding parts outside the printed area.

Further preferably, a sheet processing device according to another aspect of the invention also has a controller configured to control operation of the eraser based on a detection result from the detector.

This enables achieving the effect of the invention.

Further preferably in a sheet processing device according to another aspect of the invention, the detector has an imager to image the sheet; and the controller has a data processor configured to process image data captured by the imager.

This configuration enable identifying the printed parts and setting the printed area.

Further preferably in a sheet processing device according to another aspect of the invention, the eraser has a stamping mechanism configured to punch through and remove the printed area of the sheet.

This configuration enables more reliably erasing the printed area.

Another aspect of the invention is a sheet manufacturing apparatus including the sheet processing device according to the invention described above.

This aspect of the invention receives the benefits of the sheet processing device described above while also manufacturing (recycling) sheets.

A sheet manufacturing apparatus according to another aspect of the invention also has a defibrator configured to defibrate a processed sheet of which at least a surface part of the printed area of the sheet was removed by the sheet processing device; and is configured to produce recycled paper using defibrated material acquired by the defibrator.

This aspect of the invention receives the benefits of the sheet processing device described above while also manufacturing (recycling) sheets.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of a sheet processing device and a sheet manufacturing apparatus according to the invention are described below with reference to the accompanying figures.

FIG. 1is a schematic side view illustrating the configuration of a sheet processing device according to the invention disposed to the upstream side of a sheet manufacturing apparatus according to a first embodiment of the invention.FIG. 2is a schematic side view illustrating the configuration of the downstream side of a sheet manufacturing apparatus according to the first embodiment of the invention.FIG. 3is a flow chart illustrating processes executed by a sheet manufacturing apparatus according to the first embodiment of the invention.FIG. 4is a top view of the sheet processing device shown inFIG. 1.FIG. 5is a side view of the sheet processing device shown inFIG. 1.FIG. 6is a side view of the sheet processing device shown inFIG. 1.FIG. 7is a block diagram of the sheet processing device shown inFIG. 1.FIG. 8is a plan view of feedstock supplied to the sheet processing device shown inFIG. 1.FIG. 9is a flow chart describing a control operation of the controller shown inFIG. 7.

Note that for convenience below, the top as seen inFIG. 1is referred to as the top or above, the bottom as the bottom or below; the left side as the left or upstream side, and the right as the right or downstream side.

The sheet processing device1shown inFIG. 1has a detector3for detecting the printed part P printed on the feedstock M0(sheet), and an eraser4for selectively removing the printed area PA including the printed part P detected by the detector3on at least the front surface of the feedstock M0.

This enables removing selectively removing the printed area PA on at least the front surface. More specifically, the printed area PA can be selectively (efficiently) removed, and unnecessary removal of parts outside the printed area PA can be prevented. In other words, the printed part P can be removed without excess or deficiency.

The sheet manufacturing apparatus100shown inFIG. 2includes the sheet processing device1shown inFIG. 2. More specifically, the sheet manufacturing apparatus100has a defibrator13that defibrates feedstock M1(processed sheets) from which the printed area PA on at least the front surface of the feedstock M0(sheet) has been removed by the sheet processing device1, and makes sheets S (recycled paper) using the defibrated material M3produced by the defibrator13.

The invention thus comprised can therefore receive the benefits of the above sheet processing device1when manufacturing (recycling) sheets S. More specifically, because removal of material outside the printed area PA is prevented, as much fiber as possible can be supplied as the feedstock M1to the downstream side of the sheet manufacturing apparatus100. Yield is therefore improved, and sheets S with a high degree of whiteness can be formed.

The configuration of parts of the sheet manufacturing apparatus100is described next.

The sheet manufacturing apparatus100shown inFIG. 1andFIG. 2is an apparatus for making (recycling) sheets S (recycled paper) from feedstock M0, and having a first feedstock hopper7, the sheet processing device1according to the invention, a second feedstock hopper8, a feedstock supply device11, a shredder12, a defibrator13, a classifier14, a first web forming device15, a cutter16, a mixing device17, a detangler18, a second web forming device19, a sheet forming device20, a paper cutter21, and a stacker22. The sheet manufacturing apparatus100also has wetting unit231, wetting unit232, wetting unit233, wetting unit234, wetting unit235, and wetting unit236. Operation of parts of the sheet manufacturing apparatus100is controlled by a controller not shown.

As shown inFIG. 3, the sheet manufacturing method in this embodiment of the invention includes a printed area detection process, a printed area removal process, a feedstock supply process, a shredding process (refining process), a defibrating process (refining process), a classification process, a first web forming process, a cutting process, a mixing process, a detangling process, a second web forming process, a sheet forming process, and a sheet cutting process. Of these processes, the processes (sheet processing method) executed by the sheet processing device1are the printed area detection process and the printed area PA removal process.

As shown inFIG. 1, the first feedstock hopper7is the part where feedstock M0, that is, sheets (used sheets) before being processed by the sheet processing device1, is stocked. The feedstock M0in this example is fiber-containing material including fiber (particularly cellulosic fiber), and in this example is in a sheet form. In this embodiment, the feedstock M0is recovered paper, that is, sheets that have been used, but the invention is not so limited and the feedstock M0may be sheets that have not been used.

Note that the cellulose fiber may be any fibrous material containing mainly cellulose (narrowly defined cellulose) as a chemical compound, and in addition to cellulose (narrowly defined cellulose) may include hemicellulose or lignin.

The sheet processing device1according to the invention is disposed on the downstream side of the first feedstock hopper7. The sheet processing device1applies the process described below to the feedstock M0, producing feedstock M1, which is stored in the second feedstock hopper8. A feedstock supply device11is disposed on the downstream side of the second feedstock hopper8.

The feedstock supply device11is the part that executes the feedstock supply process (seeFIG. 3) supplying feedstock M1conveyed from the second feedstock hopper8to the shredder12.

The shredder12is the part that executes the shredding process (seeFIG. 3) of shredding, in air, the feedstock M1supplied from the feedstock supply device11. The shredder12has a pair of shredder blades121and a chute (hopper)122.

By turning in opposite directions of rotation, the pair of shredder blades121shred the feedstock M1passing therebetween, that is, cut the feedstock M1into small shreds M2. The size and shape of the shreds M2are preferably appropriate to the defibration process of the defibrator13, and in this example are preferably pieces 100 mm or less on a side, and are further preferably pieces that are greater than or equal to 10 mm and less than or equal to 70 mm per side.

The chute122is located below the pair of shredder blades121, and in this example is funnel-shaped. As a result, the chute122can easily catch the shreds M2that are shredded and dropped by the shredder blades121.

Above the chute122, a wetting unit231is disposed beside the pair of shredder blades121. The wetting unit231wets the shreds M2in the chute122. This wetting unit231has a filter (not shown in the figure) containing water, and is configured as a heaterless humidifier (or heated humidifier) that supplies a moist stream of air to the shreds M2by passing air through the filter. By wet air being supplied to the shreds M2, shreds M2sticking to the chute122due to static electricity can be suppressed.

The chute122connects to the defibrator13through a conduit (flow channel)241. The shreds M2collected in the chute122passes through the conduit241and are conveyed to the defibrator13.

The defibrator13is the part that executes the defibrating process (refining process) (seeFIG. 3) that defibrates the shreds M2(fiber-containing material including fiber) in a dry process in air. Defibrated material M3can be produced from the shreds M2by the defibration process of the defibrator13.

As used herein, defibrate means to break apart and detangle into single individual fibers shreds M2composed of many fibers bonded together. The resulting detangled fibers are the defibrated material M3. The shape of the defibrated material M3is strings and ribbons. The defibrated material M3may also contain clumps, which are multiple fibers tangled together into clumps.

The defibrator13in this embodiment of the invention, for example, is configured as an impeller mill having a rotor that turns at high speed, and a liner disposed around the rotor. Shreds M2introduced to the defibrator13are defibrated between the rotor and the liner.

The defibrator13, by rotation of the rotor, produces an air flow (current) from the shredder12to the classifier14. As a result, shreds M2can be suctioned from the conduit241to the defibrator13. In addition, after the defibration process, the defibrated material M3can be fed through another conduit242to the classifier14.

The defibrator13also functions to separate from the fibers materials such as resin particles bonded with the defibrated material M3(shreds M2), ink, toner, and other color material CM, and bleeding inhibitors.

The defibrator13also connects through a conduit242(flow path) to the classifier14. The defibrated material M3(fiber-containing material after defibration) is conveyed through the conduit242to the classifier14.

A blower261is disposed in the conduit242. The blower261is an air flow generator that produces a flow of air to the classifier14. This promotes conveyance of the defibrated material M3to the classifier14.

The classifier14executes a process (FIG. 3) of selecting defibrated material M3based on the length of the fibers. The classifier14sorts the defibrated material M3into first screenings M4-1, and second screenings M4-2that are larger than the first screenings M4-1. The first screenings M4-1are a size suitable to making sheets S. The second screenings M4-2include insufficiently defibrated material, and excessively clumped defibrated fiber.

The classifier14includes a drum141, and a housing142enclosing the drum141.

The drum141is a sieve comprising a cylindrical mesh body that rotates on its center axis. The defibrated material M3flows into the drum141. As the drum141rotates, defibrated material M3that is smaller than the mesh openings is selected as the first screenings M4-1, and defibrated material M3that is larger than the mesh openings is selected as the second screenings M4-2.

The first screenings M4-1drop out from the drum141.

The second screens M4-2are discharged to the conduit (flow path)243connected to the drum141. The end of the conduit243on the opposite end (downstream end) as the drum141is connected to another conduit241. The second screenings M4-2passing through conduit243merge with the shreds M2in conduit241, and flow with the shreds M2into the defibrator13. As a result, the second screenings M4-2are returned to the defibrator13and again defibrated with the shreds M2.

The first screenings M4-1from the drum141are dispersed while dropping through air, and descend toward the first web forming device15(separator) below the drum141. The first web forming device15is the part that executes a first web forming process (seeFIG. 3) forming a first web M5from the first screenings M4-1.

The first web forming device15includes a mesh belt (separation belt)151, three tension rollers152, and a suction unit (suction mechanism)153.

The mesh belt151is an endless belt on which the first screened material M4-1accumulates. This mesh belt151is mounted on three tension rollers152. By rotationally driving the tension rollers152, the first screened material M4-1deposited on the mesh belt151is conveyed downstream.

The size of the first screened material M4-1is greater than or equal to the size of the mesh in the mesh belt151. As a result, passage of the first screened material M4-1through the mesh belt151is limited, and as a result the first screened material M4-1accumulates on the mesh belt151.

Furthermore, because the first screened material M4-1is conveyed downstream by the mesh belt151as the first screened material M4-1accumulates on the mesh belt151, the first screened material M4-1is formed in a layer as a first web M5.

Color material CM is removed from the feedstock M1by the sheet processing device1, but some color material CM not completely removed by the sheet processing device1may remain. Because the color material CM is smaller than the mesh openings of the mesh belt151, the color material CM passes through the mesh belt151and precipitates. This enables removing remnants of color material CM not removed by the sheet processing device1.

The suction unit153suctions air from below the mesh belt151. As a result, color material CM that has past through the mesh belt151can be suctioned together with the air.

The suction unit153is connected to a dust collector27(collection device) through another conduit (flow path)244. Color material CM suctioned by the suction unit153are captured by the dust collector27.

Another conduit (flow path)245is also connected to the dust collector27. A blower262is disposed to the conduit245. Operation of the blower262produces suction in the suction unit153. This promotes formation of the first web M5on the mesh belt151. The first web M5is made from material from which color material CM has been removed. Operation of the blower262causes the color material CM to pass through the conduit244and reach the dust collector27.

The housing142is connected to a wetting unit232. Like the wetting unit231described above, the wetting unit232is a heaterless humidifier. As a result, wet air is supplied into the housing142. This wet air moistens the first screened material M4-1, and as a result can suppress sticking of the first screened material M4-1to the inside walls of the housing142due to static electricity.

Another wetting unit235is disposed downstream from the classifier14. This wetting unit235is configured as an ultrasonic humidifier that mists water. As a result, moisture can be supplied to (can humidify or moisten) the first web M5, and the moisture content of the first web M5can thereby be adjusted. This adjustment can also suppress sticking of the first web M5to the mesh belt151due to static electricity. As a result, the first web M5easily separates from the mesh belt151at the tension roller152from where the mesh belt151returns to the upstream side.

On the downstream side of the wetting unit235is a cutter16. The cutter16is a part that executes a cutting process (seeFIG. 3) of cutting the first web M5that has separated from the mesh belt151.

The cutter16has a propeller161that is rotationally supported, and a housing162that houses the propeller161. The first web M5is cut into pieces by the first web M5being fed into the rotating propeller161. The cut first web M5forms segments M6. The segments M6then drop down in the housing162.

The housing162is connected to another wetting unit233. Like the wetting unit231described above, the wetting unit233is a heaterless humidifier. As a result, wet air is supplied into the housing162. This wet air suppresses sticking of the segments M6to the propeller161and to the inside walls of the housing162due to static electricity.

A mixing device17is disposed on the downstream side of the cutter16. The mixing device17is the part that executes a mixing process (seeFIG. 3) of mixing the segments M6with resin P1. The mixing device17includes a resin supply device171, a conduit (flow path)172, and a blower173.

The conduit172connects to the housing162of the cutter16and the housing182of the detangler18, and is a flow path through which a mixture M7of the segments M6and resin P1passes.

The resin supply device171connects to the conduit172. The resin supply device171has a screw feeder174. By rotationally driving the screw feeder174, the resin P1can be supplied in powder or particle form to the conduit172. The resin P1supplied to the conduit172is mixed with the segments M6, forming the mixture M7.

Note that the resin P1bonds fibers together in a downstream process, and may be a thermoplastic resin or a thermosetting resin, but is preferably a thermoplastic resin. Examples of such thermoplastic resins include AS resin, ABS resin, polyethylene, polypropylene, ethylene-vinylacetate copolymer (EVA), or other polyolefin, denatured polyolefins, polymethylmethacrylate or other acrylic resin, polyvinyl chloride, polystyrene, polyethylene terephthalate, polybutylene terephthalate or other polyesters, nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, nylon 6-12, nylon 6-66 or other polyimide (nylon), polyphenylene ether, polyacetal, polyether, polyphenylene oxide, polyether ether ketone, polycarbonate, polyphenylene sulfide, thermoplastic polyimide, polyether imide, aromatic polyester, or other liquid crystal polymer, styrenes, polyolefins, polyvinyl chlorides, polyurethanes, polyesters, polyimides, polybutadienes, transpolyisoprenes, fluoroelastomers, polyethylene chlorides and other thermoplastic elastomers, as well as combinations of one or two or more of the foregoing. Preferably, a polyester or resin containing a polyester is used as the thermoplastic resin.

Additives other than resin P1may also be supplied from the resin supply device171, including, for example, coloring agents for adding color to the fiber, anti-blocking agents for suppressing clumping of the fiber and clumping of the resin P1, and flame retardants for making the fiber and manufactured sheets difficult to burn. Starch and other vegetable materials may also be used.

The blower173is disposed to the conduit172downstream from the resin supply device171. The blower173is configured to produce an air current toward the detangler18. This air current can also mix the segments M6and resin P1inside the conduit172. As a result, the mixture M7can be introduced to the detangler18as a uniform dispersion of the segments M6and resin P1. The segments M6in the mixture M7are further detangled into smaller fibers while travelling through the conduit172.

The detangler18is the part that executes the detangling process (seeFIG. 3) that detangles interlocked fibers in the mixture M7.

The detangler18includes a drum181and a housing182that houses the drum181.

The drum181is a sieve comprising a cylindrical mesh body that rotates on its center axis. The mixture M7is introduced to the drum181. By the drum181rotating, fiber in the mixture M7that is smaller than the mesh can pass through the drum181. The mixture M7is detangled in this process.

The mixture M7that is detangled in the drum181is dispersed while dropping through air, and falls to the second web forming device19located below the drum181. The second web forming device19is the part that executes the second web forming process (seeFIG. 3) forming a second web M8from the mixture M7. The second web forming device19includes a mesh belt191(separation belt), tension rollers192, and a suction unit193(suction mechanism).

The mesh belt191is an endless belt on which the mixture M7accumulates. This mesh belt191is mounted on four tension rollers192. By rotationally driving the tension rollers192, the mixture M7deposited on the mesh belt191is conveyed downstream.

Most of the mixture M7on the mesh belt191is larger than the mesh in the mesh belt191. As a result, the mixture M7is suppressed from passing through the mesh belt191, and therefore accumulates on the mesh belt191. The mixture M7is conveyed downstream by the mesh belt191as the mixture M7accumulates on the mesh belt191, and is formed in a layer as the second web M8.

The suction unit193suctions air down from below the mesh belt191. As a result, the mixture M7can be pulled onto the mesh belt191, and accumulation of the mixture M7on the mesh belt191is thereby promoted.

Another conduit246(flow path) is connected to the suction unit193. A blower263is also disposed to the conduit246. Operation of the blower263produces suction in the suction unit193.

Another wetting unit234is connected to the housing182. Like the wetting unit231described above, the wetting unit234is a heaterless humidifier. As a result, wet air is supplied into the housing182. By humidifying the inside of the housing182by adding wet air, sticking of the mixture M7to the inside walls of the housing182due to static electricity can be suppressed.

Another wetting unit236is disposed below the detangler18. This wetting unit236is configured as an ultrasonic humidifier similarly to the wetting unit235described above. As a result, moisture can be supplied to the second web M8, and the moisture content of the second web M8can thereby be adjusted. This adjustment can also suppress sticking of the second web M8to the mesh belt191due to static electricity. As a result, the second web M8easily separates from the mesh belt191at the tension roller192from where the mesh belt191returns to the upstream side.

A sheet forming device20is disposed downstream from the second web forming device19. The sheet forming device20is the part that executes the sheet forming process (seeFIG. 3) forming sheets S from the second web M8. This sheet forming device20includes a calender201and a heater202.

The calender201comprises a pair of calender rolls203, and compresses the second web M8between the calender rolls203without heating the second web M8. This process increases the density of the second web M8. The second web M8is then conveyed toward the heater202. Note that one of the pair of calender rolls203is a drive roller that is driven by operation of a motor (not shown in the figure), and the other is a driven roller.

The heater202has a pair of heat rollers204, which can heat while compressing the second web M8between the heat rollers204. The combination of heat and pressure melts the resin P1in the second web M8, and binds fibers through the molten resin P1. As a result, a sheet S is formed.

The sheet S is then conveyed to the paper cutter21. Note that one of the pair of heat rollers204is a drive roller that is driven by operation of a motor (not shown in the figure), and the other is a driven roller.

A paper cutter21is disposed downstream from the sheet forming device20. The paper cutter21is the part that executes the sheet cutting process (seeFIG. 3) that cuts the continuous sheet S into single sheets S. The paper cutter21includes a first cutter211and a second cutter212.

The first cutter211cuts the sheet S in the direction crosswise to the conveyance direction of the sheet S.

The second cutter212is downstream from the first cutter211, and cuts the sheets S in the direction parallel to the conveyance direction of the sheet S.

Sheets S of a desired size are produced by the cutting action of the first cutter211and the second cutter212. The sheets S are then conveyed further downstream and stacked in a stacker22.

A sheet processing device1according to the invention is described next.

The sheet processing device1shown inFIG. 1is disposed on the upstream side of the sheet manufacturing apparatus100, and is a device that removes color material CM in the printed part P of the feedstock M0described above.

The sheet processing device1has a conveyor2, detector3, and eraser4, which are unitized in a housing not shown.

The sheet processing device1is an apparatus that sequentially executes a printed area detection process, refining prevention agent application process, and drying process.

Note that the sheet processing device1may be disposed or connected to the feedstock supply device11(seeFIG. 2) through the second feedstock hopper8. This enables processing sheets in the sheet process and manufacturing new sheets in the sheet recycling process in a single continuous operation.

Parts of the sheet processing device1are described next.

The conveyor2conveys preprocessed feedstock M0supplied from the first feedstock hopper7downstream. The conveyor2includes a glue belt210(endless belt) used as a conveyor belt, and four tension rollers220with the glue belt210mounted around the tension rollers220. At least one tension roller220has an internal motor, which drives and turns when energized. As a result, the feedstock M0on the glue belt210can be conveyed downstream (in the direction of the arrow inFIG. 1).

The surface of the glue belt210is preferably adhesive. This enables stable conveyance of the feedstock M0, and stable execution of the printed area detection process and printed area removal process. Tension is applied to the feedstock M0during grinding in the printed area removal process described below, and using glue belt210can prevent the feedstock M0from shifting position due to grinding. Variation in the timing of the grinding step as a result of the position shifting can therefore be prevented.

Note that the same effect can be achieved when the glue belt210does not have an adhesive surface by providing a suction mechanism that pulls the feedstock M0to the glue belt210by suction through the glue belt210.

Multiple sheets of feedstock M0can also be carried on the glue belt210at one time. The orientation (positioning) of each sheet of feedstock M0on the glue belt210may also be aligned (the same) or not.

Note that the conveyor2configuration shown inFIG. 1is a belt conveyor, but the invention is not so limited and may be a configuration that conveys while holding the feedstock M0by negative pressure suction on a stage, that is, a configuration that has a platen and multiple conveyance rollers.

The detector3executes the printed area detection process for detecting the printed part P of the feedstock M0, and in this example has a camera31(imaging device) such as a CCD camera. The camera31is disposed separated from one side of the glue belt210, that is, above the top side of the glue belt210in this example. The camera31images the feedstock M0conveyed on the glue belt210.

In this example the feedstock M0is recovered paper, that is, used paper that has been printed or written on over the greater part. As a result, text, images, or other content has been printed on the feedstock M0by applying black or color toner or ink, dyes, pigments, or other color material CM to the feedstock M0. Herein, the part of the feedstock M0where color material CM is present is referred to as the printed part P. The printed part P is not limited to text, and may include symbols, graphics and images, or simply a soiled or smudged area.

The camera31is electrically connected to the controller5, and its operation is controlled by the controller5. Image data captured by the camera31is sent to the controller5.

Note that the detector3is a camera that captures a two-dimensional image in the configuration shown inFIG. 1, but the invention is not so limited, and may be a one-dimensional line sensor or scanner, for example. In this case, the detector3may be a reflective or transmissive detector.

The eraser4has a grinding tool for grinding the feedstock M0(sheet), and a pressure mechanism42for selectively increasing the contact pressure between the feedstock M0(sheet) and brush41(grinding tool) in the printed area PA. As a result, the printed area PA of the feedstock M0can be selectively abraded as described below.

As shown inFIG. 8, the printed area PA is a part of the feedstock M0containing at least the printed part P and some surrounding white space (margin), and may be rectangular, square, round, oval, or other shape, but in the configuration shown in the figure is rectangular. Note that the printed area PA may not include white space. In addition, if the printed part P is a line (row or column) of text, the printed area PA may be the area containing that line (row or column). This printed area PA is set by the controller5as described below.

The core411is connected to a motor (not shown in the figure), and the bristles412turn in the direction of the arrow when the motor is driven. The axis of rotation of the brush41is disposed substantially perpendicular to the conveyance direction of the feedstock M1. However, the invention is not so limited, and the axis of rotation may be disposed inclined a specific angle (such as greater than or equal to 5 degrees and less than or equal to 45 degrees) to the direction perpendicular to the axis of rotation.

Bristles412are implanted to the entire outside surface of the core411. The bristles412are made from a pliable resin material such as polyimide or polyester. The tips of the bristles412may be sharp or rounded.

This embodiment describes an example in which the grinding tool is a brush, but the invention is not so limited and the grinding tool may be a whetstone or file, for example.

When the brush41turns in the direction of the arrow in the figure while in contact with the sheet S, the sheet S is abraded (ground). Note that the brush41may be configured to turn in the opposite direction as shown in the figure, or to periodically alternate between clockwise and counterclockwise rotation. The brush41may also be configured to move (bidirectionally) in the same direction as the direction of rotation as the brush41turns.

The pressure mechanism42includes a roller group43as pressure members, and a drive source44that drives the rollers of the roller group43independently.

As shown inFIG. 4, the roller group43is disposed to a position opposite the brush41with the glue belt210therebetween, and its position in the conveyance direction of the feedstock M0is the same as the brush41. The roller group43includes multiple (11in the configuration shown in the figure) short rollers431.

The short rollers431have a cylindrical outside shape, and are disposed with the axis of rotation substantially perpendicular to the conveyance direction of the feedstock M1. The short rollers431are disposed substantially coaxially in a line across the width of the glue belt210.

Each of the short rollers431is configured movably to and away from the brush41. The short rollers431intermittently apply pressure through the glue belt210to the opposite side of the feedstock M0as the brush41(the bottom side as seen inFIG. 1,FIG. 5, andFIG. 6).

The pressure mechanism42thus has a roller group43(pressure members) disposed movably to and away from the brush41(grinding tool), and directly or indirectly (indirectly in this embodiment) applies pressure to the feedstock M0(sheet) from the opposite side of the feedstock M0(sheet) as the brush41(grinding tool). As a result, the printed area PA of the feedstock M0can be pushed against the brush41and ground.

The sheet processing device1also has a conveyor2that conveys the feedstock M0(sheet) by means of a glue belt210(conveyor belt) at least between the detector3and eraser4, and the roller group43(pressure member) pushes the feedstock M0(sheet) through the glue belt210(convey belt) against the brush41(grinding tool). The roller group43applying excessive pressure to the feedstock M0can therefore be prevented. As a result, unintentionally damaging the magneto-optical can be prevented.

The plural short rollers431(pressure elements) are disposed across the width of the glue belt210, that is, in a direction intersecting the conveyance direction of the feedstock M0(sheet) in the eraser4. As a result, as described below, pressure can be applied to the printed area PA regardless of where on the feedstock M0the printed area PA is located. This means that the printed area PA can be removed by pushing the brush41against the printed area PA regardless of where on the feedstock M0the printed area PA is located.

Furthermore, the size of the pressure elements can be reduced and a relatively large number of pressure elements can be provided by using rollers or pins (short rollers431in this embodiment). As a result, even relatively small printed areas PA can be precisely ground and removed.

The short rollers431may be configured to rotate or no rotate.

The drive source44can move the short rollers431independently up and down, that is, to and away from the brush41. Insofar as this ability is provided, the configuration of the drive source44is not specifically limited, and the drive source44may be configured with multiple drive elements such as air cylinders or solenoids connected to the individual short rollers431. The drive source44can be electrically connected to the controller5and operation controlled by energizing the drive elements.

As shown inFIG. 5, until the feedstock M0is conveyed to the eraser4in the sheet processing device1, the glue belt210and brush41are separated. When an area outside the printed area PA of the feedstock M0(that is, white space) passes between the brush41and short rollers431, the short rollers431do not operate. Timed to when the printed area PA of the feedstock M0passes between the brush41and short rollers431, one or more short rollers431move to the brush41, and push the glue belt210and feedstock M1up, causing the printed area PA to contact the brush41.

As a result, contact pressure between brush41and the printed area PA of the feedstock M0increases, the surface part of the printed area PA is abraded, and the printed part P, that is, the color material CM, is removed from the feedstock M0without excess or deficiency. Specifically, because grinding of areas outside the printed area PA is prevented, the amount of fiber supplied as feedstock M1to the downstream sheet manufacturing apparatus100can be increased as much as possible. Yield is therefore good and sheets S with a high degree of whiteness can be produced.

Note that the surface part as referred to herein means the portion to a depth of 1/10 to ½ of the thickness from the surface. While the whiteness of the manufactured sheets S can be improved by removing at least the surface part of the printed area PA, grinding to a greater depth from the surface part is preferable when the color material CM has penetrated to a greater depth or the color material CM is relatively dark. Depending on the degree of color material CM penetration and the color of the color material CM, the feedstock M1may be ground until through-holes are formed. The depth of color material CM penetration can be estimated from the type of color material CM, the type of fiber in the feedstock M0, the density, and other factors. If this information is already known, the contact pressure of the short rollers431and brush41is desirably adjusted.

In the example inFIG. 4, when there are two printed parts P on the feedstock M0and two printed areas PA are set, the printed areas PA are removed as described below. These two printed areas PA are identified from the upstream side inFIG. 4as printed area PA1and printed area PA2. The eleven short rollers431are identified from the upstream side inFIG. 4as short roller431a, short roller431b, short roller431c, short roller431d, short roller431e, short roller431f, short roller431g, short roller431h, short roller431i, short roller431j, short roller431k.

In the example inFIG. 4A, short roller431dcorresponding to printed area PA1, that is, at the same position in the direction perpendicular to the glue belt210, and short roller431hcorresponding to printed area PA2, that is, at the same position in the direction perpendicular to the glue belt210, operate, and the other short rollers431do not operate. More specifically, only short roller431dand short roller431hlocated at the positions capable of grinding printed area PA1and printed area PA2push the feedstock M0against the brush41.

The roller group43(pressure member) thus has multiple short rollers431(pressure elements), and selectively drives the short rollers431(pressure elements) to increase the contact pressure of the brush41(grinding tool) on specific parts of the feedstock M0(sheet). Grinding parts outside the printed area PA can therefore be more reliably prevented, and the amount of fiber supplied as feedstock M1to the sheet manufacturing apparatus100downstream can be further increased. Sheets S can therefore be manufactured with good yield.

The glue belt210and brush41are separated until the feedstock M0is conveyed to the eraser4in this configuration, but the invention is not so limited and the glue belt210and brush41may be in contact.

The brush41in this embodiment is configured to rotate even when not grinding the feedstock M0, but the invention is not so limited, and may be configured to turn only when grinding the feedstock M0, that is, so the short rollers431turn only when the feedstock M0is pushed up.

As shown inFIG. 4, the controller5includes a CPU51(processor) and storage52(memory, hard disk drive, for example), and controls operation of the conveyor2, detector3, and eraser4. The controller5controls operation of the eraser4based on output from the detector3. This enables achieving the effects described above.

The controller5in this embodiment may be disposed where desired in the sheet processing device1, or it may be an externally connected control device. In configured as an external device, the control device and sheet manufacturing apparatus may communicate wirelessly or by wire, or through the Internet, for example. In addition, a configuration in which only the CPU51or the storage52is an external device is also conceivable.

Note that there may also be multiple dedicated controllers for controlling the conveyor2, detector3, and eraser4.

In this embodiment, the controller5is dedicated to the sheet processing device1, and separate controllers are provided for the shredder12to sheet forming device20, but the invention is not so limited. For example, the controllers of devices from the shredder12to the sheet forming device20may also be configured to control other parts of the sheet processing device1, and the controller5may control devices from the shredder12to the sheet forming device20in addition to controlling parts of the sheet processing device1.

The CPU51executes programs stored in storage52. The CPU51functions as a data processor that processes image data captured by the camera31. As described above, the CPU51also identifies the printed part P and defines the printed area PA.

The detector3has a camera31(imaging unit) that images the feedstock M0(sheet), and the controller5has a CPU51that functions as a data processor that processes image data captured by the camera31(imaging unit). This enables identifying the printed part P and defining the printed area PA.

The storage52in this example is rewritable nonvolatile memory. Programs such as programs related to sheet processing as described above are stored in storage52, and the programs are run by the CPU51.

A control operation of the controller5of the sheet processing device1is described next with reference to the flow chart inFIG. 9.

Sheet processing starts in step S101. In other words, the conveyor2and brush41are operated.

Next, the supplied and conveyed feedstock M0is imaged (step S102). Note that when the feedstock M0is supplied by a feeding device not shown, the timing of detector3(camera31) operation, that is, imaging, may be adjusted to the conveyance speed of the conveyor2, or the timing of imaging may be adjusted by a timer based on calculating the time required for the feedstock M0to be conveyed to the imaging area.

Next, in step S103, the printed part P is detected in the image acquired in step S102(printed part detection process). For example, the image may be divided into specific areas, and when the brightness in each area is less than or equal to a specific threshold, the controller5may decide color material CM was detected, but if the brightness is greater than the specific threshold, decide there is no color material CM. The printed part P can be determined based on this information.

Next, in step S104, the controller5defines the printed area PA containing the printed part P identified in step S103(seeFIG. 8).

Next, in step S105, the short rollers431to drive are selected from the roller group43. This selected is made based, for example, on information such as the number of printed areas PA, the location, and the size of the printed areas PA in the image.

The short rollers431selected in step S105are then driven to selectively remove the printed areas PA (step S106). Note that the timing for driving the short rollers431is calculated based on the conveyance speed of the feedstock M0and the distance from the detector3to the eraser4, for example.

The time that the short rollers431are pressed against the feedstock M0can also be calculated based on the length of the printed area PA in the conveyance direction and the conveyance speed, for example.

As described above, the sheet processing device1moves the short rollers431toward the brush41timed to when the printed area PA on the feedstock M0passes between the brush41and short rollers431, raising the feedstock M1with the glue belt210and pushing the printed area PA in contact with the brush41. This increases the contact pressure between the printed area PA on the feedstock M0and the brush41, and the surface part of the printed area PA is ground. As a result, the printed part P, that is, the color material CM, is removed without excess or deficiency from the feedstock M0. More specifically, because grinding of areas outside the printed area PA is prevented, the amount of fiber supplied as feedstock M1to the downstream sheet manufacturing apparatus100can be increased as much as possible. Sheets S can therefore be manufactured with good yield.

FIG. 10is a top view illustrating the configuration of a sheet processing device according to the invention disposed to the upstream side of a sheet manufacturing apparatus according to a second embodiment of the invention.FIG. 11is a schematic side view of the sheet processing device shown inFIG. 10.FIG. 12is a schematic side view of the sheet processing device shown inFIG. 10.

A second embodiment of a sheet processing device according to the invention is described below with reference to the accompanying figures, focusing on the differences between this and the foregoing embodiment, and omitting or simplifying further description of like elements.

This embodiment is the same as the first embodiment except for the configuration of the pressure member.

As shown inFIG. 10, the eraser4has a dot impact head45(pressure elements). The dot impact head45is disposed to a position opposite the brush41with the glue belt210therebetween, and its position in the conveyance direction of the feedstock M0is the same as the brush41.

The dot impact head45has multiple (17in this example) pressure pins (pins)451disposed across the width of the glue belt210, that is, in a direction intersecting the conveyance direction of the feedstock M0.

As shown inFIG. 11andFIG. 12, the pressure pins451are disposed substantially perpendicularly across the width of the glue belt210(across the width of the feedstock M0being conveyed). The pressure pins451are connected to the drive source44, and configured to move to and away from the brush41by driving the drive source44.

The distal ends of the pressure pins451, that is, the ends on the glue belt210side, are rounded. As a result, damage to the glue belt210when the pressure pins451push the glue belt210can be prevented.

As shown inFIG. 11, when the area outside the printed area PA of the feedstock M0(that is, white space) passes between the brush41and pressure pins451, the pressure pins451do not operate. Timed to when the printed area PA of the feedstock M0passes between the brush41and pressure pins451, selected pressure pins451move toward the brush41and push the glue belt210and feedstock M1up, causing the printed area PA to contact the brush41. Note that in this embodiment only the pressure pins451of the dot impact head45aligned with the printed area PA, that is, the pressure pins451indicated by the black dots inFIG. 10, operate.

As a result, contact pressure between the brush41and the printed area PA of the feedstock M0increases, the surface part of the printed area PA is abraded, and the printed part P, that is, the color material CM, is removed from the feedstock M0.

Because the pressure pins451are relatively small, even relatively small printed areas PA can be precisely removed. For example, the printed area PA can be set to the printed part P alone. In this case, the controller5preferably inverts the shape of the printed part P and drives only those pressure pins451corresponding to the specific areas of the inverted shape.

FIG. 13is a top view illustrating the configuration of a sheet processing device according to the invention disposed to the upstream side of a sheet manufacturing apparatus according to a third embodiment of the invention.

A third embodiment of a sheet manufacturing apparatus according to the invention is described below with reference to the accompanying figures, focusing on the differences between this and the foregoing embodiments, and omitting or simplifying further description of like elements.

This embodiment is the same as the second embodiment except for the arrangement of the pressure elements.

As shown inFIG. 13, the dot impact head45in this embodiment has two rows452of pressure pins451extending across the width of the glue belt210side by side in the conveyance direction. The pressure pins451in each row452are offset from each other across the width of the glue belt210.

This configuration enables reducing the pitch between the pressure pins451as seen from the conveyance direction of the feedstock M0without reducing the diameter of the pressure pins451. As a result, even smaller printed areas PA can be removed with good precision.

Note that this embodiment has two rows452of pressure pins451, but the invention is not so limited and there may be three or more rows.

FIG. 14is a top view illustrating the configuration of a sheet processing device according to the invention disposed to the upstream side of a sheet manufacturing apparatus according to a fourth embodiment of the invention.

A fourth embodiment of a sheet manufacturing apparatus according to the invention is described below with reference to the accompanying figures, focusing on the differences between this and the foregoing embodiments, and omitting or simplifying further description of like elements.

This embodiment is the same as the first embodiment except for the configuration of the eraser.

As shown inFIG. 14, the dot impact head45and the brush41in this embodiment are offset from each other in the conveyance direction of the feedstock M0, and the dot impact head45is located upstream from the brush41.

The dot impact head45(pressure member) applies pressure to upwardly deform the printed area PA of the feedstock M0(sheet) before the brush41(grinding tool) grinds the printed area PA. The feedstock M0with upward deformations is then conveyed downstream, and only these upwardly protruding parts, that is, only the printed area PA, are ground. As a result, grinding areas other than the printed area PA can be more effectively prevented, and the amount of fiber supplied as feedstock M1to the downstream sheet manufacturing apparatus100can be increased. Sheets S can therefore be manufactured with good yield.

FIG. 15is a side view of a pressure member of a sheet processing device according to the invention disposed to the upstream side of a sheet manufacturing apparatus according to a fifth embodiment of the invention.FIG. 16is a side view of the conveyor and grinding tool of the sheet processing device shown inFIG. 15.

A fifth embodiment of a sheet manufacturing apparatus according to the invention is described below with reference to the accompanying figures, focusing on the differences between this and the foregoing embodiments, and omitting or simplifying further description of like elements.

This embodiment is the same as the first embodiment except for the configuration of the eraser and conveyor.

As shown inFIG. 15, the distal ends of the pressure pins451of the dot impact head45in this embodiment are pointed. As a result, pressure can be precisely applied to the printed area PA even when the printed area PA is small or has a complicated shape.

A flexible platen46is disposed to a position opposite the dot impact head45in the sheet processing device1according to this embodiment. When the pressure pins451apply pressure to the feedstock M0, the platen46deforms with the printed area PA of the feedstock M0, and supports the parts outside the printed area PA of the feedstock M0. As a result, the printed area PA can be more reliably deformed, and unintentional deformation of parts outside the printed area PA can be prevented.

As shown inFIG. 15, this embodiment disposes a flexible protective sheet47between the feedstock M0and the pressure pins451when the pressure pins451apply pressure to the feedstock M0. Unintentionally damaging the feedstock M0can thereby be prevented.

After the printed area PA is deformed, the printed area PA is held to a conveyor platen230(conveyor2) as shown inFIG. 16, and the printed area PA is pushed against the brush41. As a result, contact pressure can be increased only in the printed area PA, and the printed area PA can be removed.

This fifth embodiment thus has the same effect as the other embodiments described above.

FIG. 17is a section view of the eraser of the sheet processing device disposed to the upstream side of a sheet manufacturing apparatus according to the sixth embodiment of the invention.

A sixth embodiment of a sheet manufacturing apparatus according to the invention is described below with reference to the accompanying figures, focusing on the differences between this and the foregoing embodiments, and omitting or simplifying further description of like elements.

This embodiment is the same as the first embodiment except for the configuration of the eraser.

The eraser4has a stamping mechanism48that punches through and removes the printed area PA of the feedstock M0(sheet). As a result, the printed area PA can be reliably removed.

The stamping mechanism48has multiple punches481. The punches481are cylindrical and the distal ends, that is, the end that contacts the feedstock M0, forms a cutter with the outside diameter narrowing to the distal end. As a result, the printed area PA can be reliably punched and removed. Furthermore, because the punches481are hollow, the material removed from the feedstock M0can be recovered.

This sixth embodiment thus has the same effect as the other embodiments described above.

Preferred embodiments of a sheet manufacturing apparatus according to the invention are described above, but the invention is not so limited. Parts of the sheet manufacturing apparatus may also replaced with equivalent configurations having the same function. Other configurations may also be added as desired.

A sheet manufacturing apparatus according to the invention may also be a combination of any two or more desirable configurations (features) of the embodiments described above.

The embodiments described above describe configurations in which the used sheets being recycled are printed on one side, but the invention is not so limited and the sheets may be printed on both sides. In this case, both sides may be processed by detecting the printed part of one side and removing the printed area, and then detecting the printed part of the other side and removing the printed area.

The foregoing embodiments also describe a continuous process of detecting the printed part of one sheet (feedstock) and removing the printed area of that sheet, then sequentially processing the next sheet (feedstock) by repeating the same steps, but the invention is not so limited. For example, a batch process of detecting the printed parts of multiple sheets (feedstock), numbering the detection results (images), and then sequentially removing the printed areas of the multiple sheets (feedstock) based on the numbering information is also conceivable.

The foregoing embodiments also describe configurations in which the pressure member moves to and away from the grinding tool, but the invention is not so limited. For example, configurations in which the grinding tool moves to and away from the sheet (feedstock) are also conceivable. In this case, a platen or other support member is preferably disposed instead of a pressure member on the opposite side of the conveyor as the grinding tool.

Yet further, pressure elements may be disposed to the grinding tool. In this case, the grinding tool may be a pliable abrasive sheet, for example, and the surface of the abrasive sheet may be made to protrude in parts by pushing the abrasive sheet by pressure elements to remove the printed area.

The entire disclosure of Japanese Patent Application No. 2017-226363, filed Nov. 24, 2017 is expressly incorporated by reference herein.