US20140255071A1 - Image forming apparatus - Google Patents
Image forming apparatus Download PDFInfo
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- US20140255071A1 US20140255071A1 US14/192,528 US201414192528A US2014255071A1 US 20140255071 A1 US20140255071 A1 US 20140255071A1 US 201414192528 A US201414192528 A US 201414192528A US 2014255071 A1 US2014255071 A1 US 2014255071A1
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- US
- United States
- Prior art keywords
- recording medium
- interval
- sheet
- passing path
- sheet passing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H7/00—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles
- B65H7/02—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H9/00—Registering, e.g. orientating, articles; Devices therefor
- B65H9/20—Assisting by photoelectric, sonic, or pneumatic indicators
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H5/00—Feeding articles separated from piles; Feeding articles to machines
- B65H5/06—Feeding articles separated from piles; Feeding articles to machines by rollers or balls, e.g. between rollers
- B65H5/062—Feeding articles separated from piles; Feeding articles to machines by rollers or balls, e.g. between rollers between rollers or balls
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H5/00—Feeding articles separated from piles; Feeding articles to machines
- B65H5/26—Duplicate, alternate, selective, or coacting feeds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H85/00—Recirculating articles, i.e. feeding each article to, and delivering it from, the same machine work-station more than once
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H9/00—Registering, e.g. orientating, articles; Devices therefor
- B65H9/004—Deskewing sheet by abutting against a stop, i.e. producing a buckling of the sheet
- B65H9/006—Deskewing sheet by abutting against a stop, i.e. producing a buckling of the sheet the stop being formed by forwarding means in stand-by
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
- G03G15/23—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 specially adapted for copying both sides of an original or for copying on both sides of a recording or image-receiving material
- G03G15/231—Arrangements for copying on both sides of a recording or image-receiving material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2301/00—Handling processes for sheets or webs
- B65H2301/30—Orientation, displacement, position of the handled material
- B65H2301/33—Modifying, selecting, changing orientation
- B65H2301/332—Turning, overturning
- B65H2301/3321—Turning, overturning kinetic therefor
- B65H2301/33214—Turning, overturning kinetic therefor about an axis perpendicular to the direction of displacement and parallel to the surface of material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2301/00—Handling processes for sheets or webs
- B65H2301/30—Orientation, displacement, position of the handled material
- B65H2301/33—Modifying, selecting, changing orientation
- B65H2301/333—Inverting
- B65H2301/3331—Involving forward reverse transporting means
- B65H2301/33312—Involving forward reverse transporting means forward reverse rollers pairs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2404/00—Parts for transporting or guiding the handled material
- B65H2404/60—Other elements in face contact with handled material
- B65H2404/61—Longitudinally-extending strips, tubes, plates, or wires
- B65H2404/611—Longitudinally-extending strips, tubes, plates, or wires arranged to form a channel
- B65H2404/6111—Longitudinally-extending strips, tubes, plates, or wires arranged to form a channel and shaped for curvilinear transport path
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2511/00—Dimensions; Position; Numbers; Identification; Occurrences
- B65H2511/20—Location in space
- B65H2511/22—Distance
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2511/00—Dimensions; Position; Numbers; Identification; Occurrences
- B65H2511/50—Occurence
- B65H2511/51—Presence
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2553/00—Sensing or detecting means
- B65H2553/60—Details of intermediate means between the sensing means and the element to be sensed
- B65H2553/61—Mechanical means, e.g. contact arms
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2553/00—Sensing or detecting means
- B65H2553/80—Arangement of the sensing means
- B65H2553/82—Arangement of the sensing means with regard to the direction of transport of the handled material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2701/00—Handled material; Storage means
- B65H2701/10—Handled articles or webs
- B65H2701/13—Parts concerned of the handled material
- B65H2701/131—Edges
- B65H2701/1311—Edges leading edge
Definitions
- the present invention relates to an image forming apparatus including a double-sided printing function.
- image forming apparatuses such as a multifunction printer (MFP) including functions of a printer, a copying machine, FAX, and the like have been in widespread use.
- MFP multifunction printer
- the image forming apparatuses generally include almost all functions necessary to complete office work, are compact, do not take up too much space, and are also excellent in terms of costs.
- the widespread use of these image forming apparatuses is expected to increase.
- some image forming apparatuses include the double-sided printing function which forms an image on one side of a printing sheet and thereafter forms an image on the reverse side of the printing sheet (for example, see PTL 1).
- double-sided printing an image is also formed on the reverse side by forming an image on one side of the printing sheet in an image forming section and then feeding and reversing the sheet through a double-sided sheet passing path to feed the sheet again into the image forming section.
- inter-sheet processing is performed in which, while a sheet with an image formed on one side is being transported along a double-sided sheet passing path, an image is formed on another sheet to be transported on the sheet passing path on which image formation is performed (also referred to as interleave processing).
- inter-sheet distance the distance between sheets to be transported on the sheet passing path (that is, the distance between the end of a preceding sheet and the leading end of a subsequent sheet, and hereinafter, referred to as an inter-sheet distance) becomes very short.
- the present invention has been made in consideration of the above-described situation, and an object of the invention is to provide an image forming apparatus capable of keeping the detection precision of a sensor constant, the sensor being configured to detect the passage of a sheet in a sheet passing path.
- an image forming apparatus that forms an image on one side of a recording medium by an image forming section and then forms an image on another side of the recording medium
- the apparatus including: a first sheet passing path that transports the recording medium housed in a sheet-feeding tray to the image forming section; a second sheet passing path that reverses the recording medium with an image formed on one side and causes the recording medium to join the first sheet passing path; a registration sensor that is placed near a joining position of the first sheet passing path and the second sheet passing path and that corrects a leading end position of the recording medium transported; and a top sensor that is placed at a position away from the registration sensor toward a downstream side of a transport direction of the recording medium by a predetermined distance and that specifies a distance between the recording media transported,
- the second sheet passing path includes: a first interval that transports the recording medium with an image formed on one side, in a substantially horizontal direction; and a second interval that transports the recording medium from an end position of the first interval
- the invention it is possible to keep detection precision of a sensor constant, the sensor detecting the passage of a sheet in a sheet passing path.
- FIG. 1 is a sectional view showing the configuration of an image forming apparatus according to an embodiment of the invention
- FIG. 2 is a diagram showing the configuration of a printing apparatus in the embodiment of the invention.
- FIGS. 3A and 3B are an enlarged view of an image forming apparatus according to an embodiment of the invention and a diagram showing a moving trajectory of a sheet;
- FIGS. 4A and 4B are diagrams illustrating how a sheet is transported on a top sensor.
- FIG. 1 is a sectional view showing the configuration of image forming apparatus (MFP) 100 .
- Image forming apparatus 100 takes out a recording medium (hereinafter referred to as “sheet”) housed in cassette (sheet-feeding tray) 10 or multi-purpose tray (MPT) (manual sheet-feeding tray) 20 , delivers the recording medium to printing apparatus 30 , prints image data on the sheet in printing apparatus 30 , and ejects the sheet on which the image data is printed to sheet ejection port 40 .
- sheet a recording medium housed in cassette (sheet-feeding tray) 10 or multi-purpose tray (MPT) (manual sheet-feeding tray) 20 , delivers the recording medium to printing apparatus 30 , prints image data on the sheet in printing apparatus 30 , and ejects the sheet on which the image data is printed to sheet ejection port 40 .
- sheet recording medium housed in cassette (sheet-feeding tray) 10 or multi-purpose tray (MPT) (manual sheet-feeding tray) 20 .
- MPT multi-purpose tray
- FIG. 2 is a conceptual diagram of printing apparatus 30 in FIG. 1 .
- Printing apparatus 30 includes a double-sided printing function which forms an image on one side of a sheet (recording medium) and thereafter forms an image on the other side of the sheet.
- Printing apparatus 30 shown in FIG. 2 has single-sided sheet passing path 31 (solid line), double-sided sheet passing path 32 (broken line), and MPT sheet passing path 33 (one-dot-chain line) as sheet passing path along which the sheet is transported.
- Single-sided sheet passing path 31 is a transporting path along which the sheet is transported during single-sided printing or double-sided printing, and is a transporting path along which sheet feeding, image formation, fixation, and sheet ejection are performed.
- Double-sided sheet passing path 32 is a sheet passing path along which the sheet is transported during double-sided printing.
- Double-sided sheet passing path 32 includes sheet passing path 32 a for reversing (switchback) sheet, sheet passing path 32 b for causing the reversed sheet to join single-sided sheet passing path 31 again, and sheet passing path 32 c for feeding the sheet into sheet passing path 32 b from single-sided sheet passing path 31 .
- MPT sheet passing path 33 is a transporting path along which the sheet is transported from MPT 20 to single-sided sheet passing path 31 .
- Top sensor 301 has a detection arm portion which rotates around an axis, and the detection arm portion is provided so as to protrude inward of single-sided sheet passing path 31 .
- Top sensor 301 detects whether or not a sheet is passing over top sensor 301 (whether or not a sheet comes into contact with the detection arm portion). Specifically, top sensor 301 generates an OFF signal when no sheet is passing over top sensor 301 and generates an ON signal when a sheet is passing over top sensor 301 .
- Image forming section 302 includes transfer roller 302 a , OPC (Organic Photo Conductor) 302 b , developing roller 302 c , and supply roller 302 d .
- Image forming section 302 transfers a toner image according to image data to the transported sheet, thereby forming an image on the sheet.
- Fixing section 303 includes pressing roller 303 a and heating roller 303 b . Fixing section 303 fixes the toner image transferred to the sheet.
- Sheet ejection sensor 304 detects whether or not a sheet is passing over sheet ejection sensor 304 . Specifically, similarly to top sensor 301 , sheet ejection sensor 304 generates an OFF signal when no sheet is passing over sheet ejection sensor 304 and generates an ON signal when a sheet is passing over sheet ejection sensor 304 .
- Sheet ejection roller 305 is placed at a position subsequent to fixing section 303 and transports the transported sheet in the direction of switching lever 306 .
- Switching lever 306 is a switching lever configured to turn around an axis and including a guide extending from the axis toward image forming section 302 and switches the transportation destination of the sheet transported by sheet ejection roller 305 to any one of single-sided sheet passing path 31 and double-sided sheet passing path 32 .
- switching lever 306 In a state where switching lever 306 is at position 306 a , the sheet is transported in the direction of ejection section 307 on sheet passing path 32 c .
- switching lever 306 is at position 306 b
- the sheet is transported in the direction of ejection section 307 on single-sided sheet passing path 31 .
- Ejection section 307 includes rollers 307 a , 307 b , and 307 c placed in proximity to sheet ejection port 40 .
- Rollers 307 a and roller 307 b constitute an ejection roller that ejects a sheet transported on single-sided sheet passing path 31 to sheet ejection port 40 .
- roller 307 b and roller 307 c constitute a reverse roller (switchback roller) that reverses the transport direction of the sheet transported on double-sided sheet passing path 32 (sheet passing path 32 a ). That is, roller 307 b , which is a roller in a set of ejection rollers, is shared as a roller in a set of reverse rollers.
- the ejection rollers and the reverse rollers include three rollers 307 a , 307 b , and 307 c , and the reverse rollers are placed above the ejection rollers.
- rollers 307 a , 307 b , and 307 c when the sheet transported on single-sided sheet passing path 31 is ejected to sheet ejection port 40 is referred to as “forward rotation processing,” and rotation processing reverse to “forward rotation processing” is referred to as “reverse rotation processing.” That is, in the forward rotation processing, a sheet on single-sided sheet passing path 31 is transported by roller 307 a and roller 307 b in the direction in which the sheet is ejected to sheet ejection port 40 , and a sheet on sheet passing path 32 a is transported by roller 307 b and roller 307 c in the direction of sheet passing path 32 b . On the other hand, in the reverse rotation processing, sheet on sheet passing path 32 a is transported by roller 307 b and roller 307 c in the direction in which the sheet is ejected to sheet ejection port 40 .
- ejection section 307 pulls the sheet transported on sheet passing path 32 c to sheet passing path 32 a by the reverse rotation processing of the reverse rollers (rollers 307 b and 307 c ).
- ejection section 307 transports the sheet on sheet passing path 32 a in the direction of sheet passing path 32 b by the forward rotation processing of the reverse rollers.
- ADU (Automatic Duplex Unit) transport roller 308 and ADU transport roller 309 transport the sheet transported from ejection section 307 to sheet passing path 32 b in the direction of single-sided sheet passing path 31 . Since the two sides of the sheet that has joined single-sided sheet passing path 31 from sheet passing path 32 b have been reversed, the double-sided printing is enabled in printing apparatus 30 .
- ADU sensor 310 detects whether or not a sheet has passed over ADU sensor 310 , thereby detecting that the sheet is being transported along sheet passing path 32 b.
- Pick roller 311 a and separation roller 311 b take out sheets one by one from cassette 10 , and feed roller 312 delivers the taken-out sheet to single-sided sheet passing path 31 .
- Pickup sensor 313 detects whether or not the sheet has passed over pickup sensor 313 , thereby detecting that the sheet is taken out from cassette 10 .
- MPT pick roller 314 a and MPT transport roller 314 b take out sheets one by one from MPT 20 , and delivers the taken-out sheet from MPT sheet passing path 33 to single-sided sheet passing path 31 .
- Registration sensor 315 detects whether or not a sheet has passed over registration sensor 315 .
- Registration roller 316 corrects the leading end position of the sheet to be transported on the basis of a position detected by registration sensor 315 . This causes an image to be printed and a fed sheet to be synchronized with each other.
- FIG. 3A is an enlarged view of single-sided sheet passing path 31 along which a sheet housed in cassette 10 is transported to image forming section 302 and double-sided sheet passing path 32 (portion A shown in FIG. 1 and FIG. 2 ) which causes a reversed sheet with an image on one side to join single-sided sheet passing path 31 .
- FIG. 3B shows a moving trajectory of a sheet to be transported in FIG. 3A .
- Single-sided sheet passing path 31 shown in FIG. 3A and FIG. 3B is formed so as to include an interval (third interval) in which a sheet substantially draws the same moving trajectory as a moving trajectory of a sheet in a predetermined interval (second interval) of double-sided sheet passing path 32 with registration sensor 315 as one end point.
- Registration sensor 315 is placed near a joining position of single-sided sheet passing path 31 and double-sided sheet passing path 32 .
- an interval between point B and point C in double-sided sheet passing path 32 is referred to as a second interval.
- an interval between point B′ and point C′ in single-sided sheet passing path 31 is referred to as a third interval. That is, the shape (the moving trajectory of the sheet) of the third interval is substantially the same as the shape (the moving trajectory of the sheet) of the second interval.
- Point B represents the placement position of registration sensor 315 .
- point B is near a position where double-sided sheet passing path 32 joins single-sided sheet passing path 31 and is a position where the sheet passing path substantially becomes linear.
- the second interval is an interval which extends toward an upstream side of the transport direction of the sheet with a position (the placement position of registration sensor 315 in FIG. 3A and FIG. 3B ) in double-sided sheet passing path 32 near the joining position of single-sided sheet passing path 31 and double-sided sheet passing path 32 as one end point.
- Point B′ is a position in the third interval corresponding to point B of the second interval, and in the example of FIG. 3A and FIG. 3B , is a position where the sheet passing path substantially becomes linear.
- double-sided sheet passing path 32 includes a first interval in which a sheet with an image formed on one side is substantially transported in a horizontal direction, and a second interval which is placed at a position subsequent to the first interval, rises toward registration sensor 315 , and joins single-sided sheet passing path 31 .
- point C (that is, the other end point of the second interval) is, for example, the start position (rising start position) of the second interval in double-sided sheet passing path 32 which rises toward registration sensor 315 and joins single-sided sheet passing path 31 .
- Point C′ is a position in the third interval corresponding to point C of the second interval.
- Trajectory 32 ′ (dotted line) shown in FIG. 3A and FIG. 3B represents a moving trajectory of a sheet in double-sided sheet passing path 32 when a moving trajectory (solid line) of sheet between point B and point C of double-sided sheet passing path 32 is superimposed on a moving trajectory (broken line) of a sheet between point B′ and point C′ of single-sided sheet passing path 31 .
- trajectory 32 ′ (corresponding to a moving trajectory (second interval) of a sheet between point B and point C of double-sided sheet passing path 32 ) between point B′ and point C′ substantially matches a moving trajectory (third interval) of a sheet of single-sided sheet passing path 31 .
- a sheet which is transported along single-sided sheet passing path 31 and a sheet which is transported along double-sided sheet passing path 32 are transported to draw the sheet passing paths having the same shape, that is, the same moving trajectory. For this reason, the sheet to be transported along single-sided sheet passing path 31 and the sheet to be transported along sheet passing path 32 a have a similar bending tendency.
- a sheet passing path which is placed at a position subsequent to the second interval and the third interval substantially becomes linear. For this reason, a sheet having a similar bending tendency in the second interval or the third interval is transported to top sensor 301 placed at a position subsequent to registration sensor 315 with a similar bending tendency.
- the sheet which is transported to top sensor 301 has a similar bending tendency even when the sheet is transported along any sheet passing path of single-sided sheet passing path 31 and double-sided sheet passing path 32 . Accordingly, the position where the sheet comes into contact with top sensor 301 is substantially the same without depending on the sheet passing path along which the sheet is transported.
- FIGS. 4A and 4B are diagrams illustrating how a sheet transported on single-sided sheet passing path 31 placed at a position subsequent to registration sensor 315 comes into contact with top sensor 301 .
- FIG. 4A and FIG. 4B it is assumed that the sheets are different in bending tendency.
- the sheet shown in FIG. 4A and the sheet shown in FIG. 4B come into contact with top sensor 301 at different positions.
- variations in the timing at which top sensor 301 detects whether or not a sheet is passing over top sensor 301 occur. That is, variations in detection precision of top sensor 301 occur.
- image forming apparatus 100 it is possible to accurately specify the inter-sheet distance between the sheets which pass through top sensor 301 .
- an accurate inter-sheet distance is specified, whereby it is possible to suppress the occurrence of a paper jam due to erroneous recognition of the inter-sheet distance.
- image forming apparatus 100 can perform processing (image formation, jam detection, and the like) which is performed using the detection result of top sensor 301 or other sensors, with high precision.
- the recording medium is not limited to a sheet, and any recording medium may be used insofar as the double-sided printing is possible.
- the present invention is useful for an image forming apparatus which can perform double-sided printing.
Abstract
Description
- 1. Field of the Invention
- The present invention relates to an image forming apparatus including a double-sided printing function.
- 2. Description of the Related Art
- In recent years, image forming apparatuses such as a multifunction printer (MFP) including functions of a printer, a copying machine, FAX, and the like have been in widespread use. The image forming apparatuses generally include almost all functions necessary to complete office work, are compact, do not take up too much space, and are also excellent in terms of costs. Thus, the widespread use of these image forming apparatuses is expected to increase.
- In addition, some image forming apparatuses include the double-sided printing function which forms an image on one side of a printing sheet and thereafter forms an image on the reverse side of the printing sheet (for example, see PTL 1). In the double-sided printing, an image is also formed on the reverse side by forming an image on one side of the printing sheet in an image forming section and then feeding and reversing the sheet through a double-sided sheet passing path to feed the sheet again into the image forming section.
-
- PTL 1
- Japanese Patent Application Laid-Open No. 2001-63892
- Along with a reduction in size and increase in printing speed of such an image forming apparatus, it is expected that sheets are transported on a sheet passing path, continuously. For example, processing is performed in which, while a sheet with an image formed on one side is being transported along a double-sided sheet passing path, an image is formed on another sheet to be transported on the sheet passing path on which image formation is performed (also referred to as interleave processing). When sheets are transported continuously, it is expected that the distance between sheets to be transported on the sheet passing path (that is, the distance between the end of a preceding sheet and the leading end of a subsequent sheet, and hereinafter, referred to as an inter-sheet distance) becomes very short.
- In this case, if variations in detection precision of a sensor (for example, a top sensor) that detects the passage of a sheet in the sheet passing path occur, the inter-sheet distance recognized by the image forming apparatus and an actual inter-sheet distance are different from each other, and a paper jam is likely to occur in the sheet passing path placed at a position subsequent to the sensor. For this reason, it is important to keep detection precision in the sensor constant, the sensor detecting the passage of a sheet in the sheet passing path.
- The present invention has been made in consideration of the above-described situation, and an object of the invention is to provide an image forming apparatus capable of keeping the detection precision of a sensor constant, the sensor being configured to detect the passage of a sheet in a sheet passing path.
- According to an aspect of the invention, there is provided an image forming apparatus that forms an image on one side of a recording medium by an image forming section and then forms an image on another side of the recording medium, the apparatus including: a first sheet passing path that transports the recording medium housed in a sheet-feeding tray to the image forming section; a second sheet passing path that reverses the recording medium with an image formed on one side and causes the recording medium to join the first sheet passing path; a registration sensor that is placed near a joining position of the first sheet passing path and the second sheet passing path and that corrects a leading end position of the recording medium transported; and a top sensor that is placed at a position away from the registration sensor toward a downstream side of a transport direction of the recording medium by a predetermined distance and that specifies a distance between the recording media transported, in which: the second sheet passing path includes: a first interval that transports the recording medium with an image formed on one side, in a substantially horizontal direction; and a second interval that transports the recording medium from an end position of the first interval to the position of the registration sensor; and the first sheet passing path includes: a third interval that transports the recording medium from a first end point at a position where a virtual line of the first interval virtually extended toward an upstream side of the transport direction of the recording medium intersects the first sheet passing path to a second end point at a position away from the registration sensor toward an upstream side of transport direction of the recording medium by a distance between the end position of the first interval and the first end point; and a fourth interval that transports the recording medium from the second end point of the third interval to the position of the top sensor in a substantially horizontal direction, in which a moving trajectory of the second interval is identical to a moving trajectory of the third interval.
- According to the invention, it is possible to keep detection precision of a sensor constant, the sensor detecting the passage of a sheet in a sheet passing path.
-
FIG. 1 is a sectional view showing the configuration of an image forming apparatus according to an embodiment of the invention; -
FIG. 2 is a diagram showing the configuration of a printing apparatus in the embodiment of the invention; -
FIGS. 3A and 3B are an enlarged view of an image forming apparatus according to an embodiment of the invention and a diagram showing a moving trajectory of a sheet; and -
FIGS. 4A and 4B are diagrams illustrating how a sheet is transported on a top sensor. - Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
- [Configuration of Image Forming Apparatus]
-
FIG. 1 is a sectional view showing the configuration of image forming apparatus (MFP) 100. -
Image forming apparatus 100 takes out a recording medium (hereinafter referred to as “sheet”) housed in cassette (sheet-feeding tray) 10 or multi-purpose tray (MPT) (manual sheet-feeding tray) 20, delivers the recording medium toprinting apparatus 30, prints image data on the sheet inprinting apparatus 30, and ejects the sheet on which the image data is printed to sheet ejection port 40. - [Configuration of Printing Apparatus 30]
-
FIG. 2 is a conceptual diagram ofprinting apparatus 30 inFIG. 1 .Printing apparatus 30 includes a double-sided printing function which forms an image on one side of a sheet (recording medium) and thereafter forms an image on the other side of the sheet. -
Printing apparatus 30 shown inFIG. 2 has single-sided sheet passing path 31 (solid line), double-sided sheet passing path 32 (broken line), and MPT sheet passing path 33 (one-dot-chain line) as sheet passing path along which the sheet is transported. - Single-sided
sheet passing path 31 is a transporting path along which the sheet is transported during single-sided printing or double-sided printing, and is a transporting path along which sheet feeding, image formation, fixation, and sheet ejection are performed. - Double-sided
sheet passing path 32 is a sheet passing path along which the sheet is transported during double-sided printing. Double-sidedsheet passing path 32 includessheet passing path 32 a for reversing (switchback) sheet,sheet passing path 32 b for causing the reversed sheet to join single-sidedsheet passing path 31 again, andsheet passing path 32 c for feeding the sheet intosheet passing path 32 b from single-sidedsheet passing path 31. - MPT
sheet passing path 33 is a transporting path along which the sheet is transported fromMPT 20 to single-sidedsheet passing path 31. -
Top sensor 301 has a detection arm portion which rotates around an axis, and the detection arm portion is provided so as to protrude inward of single-sidedsheet passing path 31.Top sensor 301 detects whether or not a sheet is passing over top sensor 301 (whether or not a sheet comes into contact with the detection arm portion). Specifically,top sensor 301 generates an OFF signal when no sheet is passing overtop sensor 301 and generates an ON signal when a sheet is passing overtop sensor 301. -
Image forming section 302 includestransfer roller 302 a, OPC (Organic Photo Conductor) 302 b, developingroller 302 c, andsupply roller 302 d.Image forming section 302 transfers a toner image according to image data to the transported sheet, thereby forming an image on the sheet. -
Fixing section 303 includes pressingroller 303 a andheating roller 303 b. Fixingsection 303 fixes the toner image transferred to the sheet. -
Sheet ejection sensor 304 detects whether or not a sheet is passing oversheet ejection sensor 304. Specifically, similarly totop sensor 301,sheet ejection sensor 304 generates an OFF signal when no sheet is passing oversheet ejection sensor 304 and generates an ON signal when a sheet is passing oversheet ejection sensor 304. -
Sheet ejection roller 305 is placed at a position subsequent to fixingsection 303 and transports the transported sheet in the direction of switchinglever 306. - Switching
lever 306 is a switching lever configured to turn around an axis and including a guide extending from the axis towardimage forming section 302 and switches the transportation destination of the sheet transported bysheet ejection roller 305 to any one of single-sidedsheet passing path 31 and double-sidedsheet passing path 32. In a state where switchinglever 306 is atposition 306 a, the sheet is transported in the direction ofejection section 307 onsheet passing path 32 c. On the other hand, in a state where switchinglever 306 is atposition 306 b, the sheet is transported in the direction ofejection section 307 on single-sidedsheet passing path 31. -
Ejection section 307 includesrollers Rollers 307 a androller 307 b constitute an ejection roller that ejects a sheet transported on single-sidedsheet passing path 31 to sheet ejection port 40. Additionally,roller 307 b androller 307 c constitute a reverse roller (switchback roller) that reverses the transport direction of the sheet transported on double-sided sheet passing path 32 (sheet passing path 32 a). That is,roller 307 b, which is a roller in a set of ejection rollers, is shared as a roller in a set of reverse rollers. Furthermore, the ejection rollers and the reverse rollers include threerollers - In the following description, the rotation processing of
rollers sheet passing path 31 is ejected to sheet ejection port 40 is referred to as “forward rotation processing,” and rotation processing reverse to “forward rotation processing” is referred to as “reverse rotation processing.” That is, in the forward rotation processing, a sheet on single-sidedsheet passing path 31 is transported byroller 307 a androller 307 b in the direction in which the sheet is ejected to sheet ejection port 40, and a sheet onsheet passing path 32 a is transported byroller 307 b androller 307 c in the direction ofsheet passing path 32 b. On the other hand, in the reverse rotation processing, sheet onsheet passing path 32 a is transported byroller 307 b androller 307 c in the direction in which the sheet is ejected to sheet ejection port 40. - That is, during the double-sided printing, first,
ejection section 307 pulls the sheet transported onsheet passing path 32 c tosheet passing path 32 a by the reverse rotation processing of the reverse rollers (rollers ejection section 307 transports the sheet onsheet passing path 32 a in the direction ofsheet passing path 32 b by the forward rotation processing of the reverse rollers. - ADU (Automatic Duplex Unit)
transport roller 308 andADU transport roller 309 transport the sheet transported fromejection section 307 tosheet passing path 32 b in the direction of single-sidedsheet passing path 31. Since the two sides of the sheet that has joined single-sidedsheet passing path 31 fromsheet passing path 32 b have been reversed, the double-sided printing is enabled inprinting apparatus 30.ADU sensor 310 detects whether or not a sheet has passed overADU sensor 310, thereby detecting that the sheet is being transported alongsheet passing path 32 b. -
Pick roller 311 a andseparation roller 311 b take out sheets one by one fromcassette 10, and feedroller 312 delivers the taken-out sheet to single-sidedsheet passing path 31.Pickup sensor 313 detects whether or not the sheet has passed overpickup sensor 313, thereby detecting that the sheet is taken out fromcassette 10. -
MPT pick roller 314 a andMPT transport roller 314 b take out sheets one by one fromMPT 20, and delivers the taken-out sheet from MPTsheet passing path 33 to single-sidedsheet passing path 31. -
Registration sensor 315 detects whether or not a sheet has passed overregistration sensor 315.Registration roller 316 corrects the leading end position of the sheet to be transported on the basis of a position detected byregistration sensor 315. This causes an image to be printed and a fed sheet to be synchronized with each other. - [Configuration of Sheet Passing Path Along which Sheet is Transported to Top Sensor 301]
-
FIG. 3A is an enlarged view of single-sidedsheet passing path 31 along which a sheet housed incassette 10 is transported to image formingsection 302 and double-sided sheet passing path 32 (portion A shown inFIG. 1 andFIG. 2 ) which causes a reversed sheet with an image on one side to join single-sidedsheet passing path 31.FIG. 3B shows a moving trajectory of a sheet to be transported inFIG. 3A . - Single-sided
sheet passing path 31 shown inFIG. 3A andFIG. 3B is formed so as to include an interval (third interval) in which a sheet substantially draws the same moving trajectory as a moving trajectory of a sheet in a predetermined interval (second interval) of double-sidedsheet passing path 32 withregistration sensor 315 as one end point.Registration sensor 315 is placed near a joining position of single-sidedsheet passing path 31 and double-sidedsheet passing path 32. - Specifically, as shown in
FIG. 3B , an interval between point B and point C in double-sidedsheet passing path 32 is referred to as a second interval. As shown inFIG. 3B , an interval between point B′ and point C′ in single-sidedsheet passing path 31 is referred to as a third interval. That is, the shape (the moving trajectory of the sheet) of the third interval is substantially the same as the shape (the moving trajectory of the sheet) of the second interval. - Point B (one end point of the second interval) represents the placement position of
registration sensor 315. In the example ofFIG. 3A andFIG. 3B , point B is near a position where double-sidedsheet passing path 32 joins single-sidedsheet passing path 31 and is a position where the sheet passing path substantially becomes linear. That is, the second interval is an interval which extends toward an upstream side of the transport direction of the sheet with a position (the placement position ofregistration sensor 315 inFIG. 3A andFIG. 3B ) in double-sidedsheet passing path 32 near the joining position of single-sidedsheet passing path 31 and double-sidedsheet passing path 32 as one end point. Point B′ is a position in the third interval corresponding to point B of the second interval, and in the example ofFIG. 3A andFIG. 3B , is a position where the sheet passing path substantially becomes linear. - In the example shown in
FIG. 3A orFIG. 3B , double-sidedsheet passing path 32 includes a first interval in which a sheet with an image formed on one side is substantially transported in a horizontal direction, and a second interval which is placed at a position subsequent to the first interval, rises towardregistration sensor 315, and joins single-sidedsheet passing path 31. In this case, point C (that is, the other end point of the second interval) is, for example, the start position (rising start position) of the second interval in double-sidedsheet passing path 32 which rises towardregistration sensor 315 and joins single-sidedsheet passing path 31. Point C′ is a position in the third interval corresponding to point C of the second interval. -
Trajectory 32′ (dotted line) shown inFIG. 3A andFIG. 3B represents a moving trajectory of a sheet in double-sidedsheet passing path 32 when a moving trajectory (solid line) of sheet between point B and point C of double-sidedsheet passing path 32 is superimposed on a moving trajectory (broken line) of a sheet between point B′ and point C′ of single-sidedsheet passing path 31. As shown inFIG. 3B ,trajectory 32′ (corresponding to a moving trajectory (second interval) of a sheet between point B and point C of double-sided sheet passing path 32) between point B′ and point C′ substantially matches a moving trajectory (third interval) of a sheet of single-sidedsheet passing path 31. - That is, in
FIG. 3A andFIG. 3B , a sheet which is transported along single-sidedsheet passing path 31 and a sheet which is transported along double-sidedsheet passing path 32 are transported to draw the sheet passing paths having the same shape, that is, the same moving trajectory. For this reason, the sheet to be transported along single-sidedsheet passing path 31 and the sheet to be transported alongsheet passing path 32 a have a similar bending tendency. - As described above, in
FIG. 3A andFIG. 3B , a sheet passing path which is placed at a position subsequent to the second interval and the third interval substantially becomes linear. For this reason, a sheet having a similar bending tendency in the second interval or the third interval is transported totop sensor 301 placed at a position subsequent toregistration sensor 315 with a similar bending tendency. Thus, the sheet which is transported totop sensor 301 has a similar bending tendency even when the sheet is transported along any sheet passing path of single-sidedsheet passing path 31 and double-sidedsheet passing path 32. Accordingly, the position where the sheet comes into contact withtop sensor 301 is substantially the same without depending on the sheet passing path along which the sheet is transported. - For example,
FIGS. 4A and 4B are diagrams illustrating how a sheet transported on single-sidedsheet passing path 31 placed at a position subsequent toregistration sensor 315 comes into contact withtop sensor 301. InFIG. 4A andFIG. 4B , it is assumed that the sheets are different in bending tendency. Thus, the sheet shown inFIG. 4A and the sheet shown inFIG. 4B come into contact withtop sensor 301 at different positions. For this reason, for example, when the sheet shown inFIG. 4A and the sheet shown inFIG. 4B are mixedly transported totop sensor 301, variations in the timing at whichtop sensor 301 detects whether or not a sheet is passing overtop sensor 301 occur. That is, variations in detection precision oftop sensor 301 occur. - In contrast, in this embodiment, it is assumed that the moving trajectories of sheets in the curved sheet passing paths of single-sided
sheet passing path 31 and double-sidedsheet passing path 32 before transportation totop sensor 301 are substantially the same. In this way, a sheet having a similar bending tendency (for example, eitherFIG. 4A orFIG. 4B ) is transported totop sensor 301 from any sheet passing path. Accordingly, the position where a sheet comes into contact withtop sensor 301 is substantially the same without depending on the sheet passing path along which the sheet is transported, and the timing at whichtop sensor 301 detects whether or not a sheet is passing overtop sensor 301 is kept constant. - Thus, according to this embodiment, in
image forming apparatus 100, it is possible to suppress variations in detection precision oftop sensor 301 which detects the passage of a sheet and to keep detection precision constant. - Accordingly, in
image forming apparatus 100, it is possible to accurately specify the inter-sheet distance between the sheets which pass throughtop sensor 301. For example, even when the inter-sheet distance is expected to be very short inimage forming apparatus 100, an accurate inter-sheet distance is specified, whereby it is possible to suppress the occurrence of a paper jam due to erroneous recognition of the inter-sheet distance. For example,image forming apparatus 100 can perform processing (image formation, jam detection, and the like) which is performed using the detection result oftop sensor 301 or other sensors, with high precision. - In the foregoing embodiment, although a case where a sheet is used as a recording medium has been described, the recording medium is not limited to a sheet, and any recording medium may be used insofar as the double-sided printing is possible.
- The present invention is useful for an image forming apparatus which can perform double-sided printing.
- The present application claims priority from Japanese application JP 2013-045232 filed on Mar. 7, 2013, the content of which is hereby incorporated by reference into this application.
Claims (9)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2013-045232 | 2013-03-07 | ||
JP2013045232A JP5325350B1 (en) | 2013-03-07 | 2013-03-07 | Image forming apparatus |
Publications (1)
Publication Number | Publication Date |
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US20140255071A1 true US20140255071A1 (en) | 2014-09-11 |
Family
ID=49595915
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/192,528 Abandoned US20140255071A1 (en) | 2013-03-07 | 2014-02-27 | Image forming apparatus |
Country Status (3)
Country | Link |
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US (1) | US20140255071A1 (en) |
JP (1) | JP5325350B1 (en) |
CN (1) | CN203909471U (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2015189580A (en) * | 2014-03-31 | 2015-11-02 | ブラザー工業株式会社 | Image formation apparatus |
JP6897466B2 (en) * | 2017-09-29 | 2021-06-30 | 住友金属鉱山株式会社 | How to separate copper from nickel and cobalt |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070147921A1 (en) * | 2005-12-26 | 2007-06-28 | Samsung Electronics Co., Ltd. | Duplex image forming apparatus and duplex image forming method |
US20090180808A1 (en) * | 2008-01-11 | 2009-07-16 | Samsung Electronics Co., Ltd. | Power transmission apparatus and image forming apparatus having the same |
US20100104341A1 (en) * | 2008-10-29 | 2010-04-29 | Oki Data Corporation | Image forming apparatus |
US20110097110A1 (en) * | 2009-10-28 | 2011-04-28 | Oki Data Corporation | Image forming apparatus |
US20130236226A1 (en) * | 2012-03-09 | 2013-09-12 | Yusuke FUNAYAMA | Image forming apparatus with compact sheet conveyance path |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5164526B2 (en) * | 2007-11-01 | 2013-03-21 | キヤノン株式会社 | Image forming apparatus |
JP5657344B2 (en) * | 2010-10-29 | 2015-01-21 | 富士ゼロックス株式会社 | Image forming apparatus |
-
2013
- 2013-03-07 JP JP2013045232A patent/JP5325350B1/en not_active Expired - Fee Related
-
2014
- 2014-02-26 CN CN201420084108.9U patent/CN203909471U/en not_active Expired - Fee Related
- 2014-02-27 US US14/192,528 patent/US20140255071A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070147921A1 (en) * | 2005-12-26 | 2007-06-28 | Samsung Electronics Co., Ltd. | Duplex image forming apparatus and duplex image forming method |
US20090180808A1 (en) * | 2008-01-11 | 2009-07-16 | Samsung Electronics Co., Ltd. | Power transmission apparatus and image forming apparatus having the same |
US20100104341A1 (en) * | 2008-10-29 | 2010-04-29 | Oki Data Corporation | Image forming apparatus |
US20110097110A1 (en) * | 2009-10-28 | 2011-04-28 | Oki Data Corporation | Image forming apparatus |
US20130236226A1 (en) * | 2012-03-09 | 2013-09-12 | Yusuke FUNAYAMA | Image forming apparatus with compact sheet conveyance path |
Also Published As
Publication number | Publication date |
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JP5325350B1 (en) | 2013-10-23 |
JP2014174256A (en) | 2014-09-22 |
CN203909471U (en) | 2014-10-29 |
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