JP4400354B2 - Sheet feeding device - Google Patents

Description

  The present invention relates to a sheet feeding apparatus.

  2. Description of the Related Art Conventionally, in image forming apparatuses such as printers and copiers, cut sheets (copy sheets) that enable continuous paper feeding are generally used as media on which images are formed. Conventionally, plain paper and high-quality paper specified by the copier manufacturer have been used. These plain papers and high-quality papers have low surface smoothness and therefore low adhesion between papers. When feeding sheets one by one from a paper stacking unit such as a paper feed tray, multiple sheets are supplied in close contact. It was relatively easy to prevent so-called double feeding.

  However, in recent years, with the diversification of recording media, it has become necessary to convey various types of sheets, including those with high surface smoothness. Other than glossy coated paper (coated paper, composite sheet with a coating color that is a kind of paint applied on both sides or one side of the sheet for the purpose of improving printing), film sheets, tracing paper, etc. As for other media, there is a high demand for conveyance in the same model. This coated paper, film sheet, tracing paper, etc. have high surface smoothness, so the adhesion between the sheets is strong, and as a result it is difficult to prevent double feeding, so special measures are required for sheet supply Become.

  For example, taking coated paper as an example, the coated paper increases in coating quality as the quality of the coated paper increases, and the white glossiness, which is an optical property, increases, and the unevenness on the surface of the base paper decreases and the surface smoothness increases. . On the other hand, when the surface smoothness is increased, the interval between the papers in contact with each other becomes narrower, the negative pressure generated in a state where air does not pass through the interval is maintained, and the adhesion between the sheets (between the sheets) is maintained. Become stronger. In particular, when smooth sheets such as coated paper are stacked in a high-humidity environment, the sheets are adsorbed and the degree of adhesion becomes higher. Film sheets and tracing paper also have high surface smoothness and high adhesion between sheets.

  When such smooth sheets with strong adhesion between sheets are fed out one by one from the paper feed tray on which the sheets are stacked, they are separated and conveyed one by one with the normal plain paper feeding device. It becomes very difficult to do. In particular, a sheet feeding device using a pull-in roll that pulls a sheet by rotating in contact with the surface of the sheet with a predetermined pressing force, and a system that presses and separates a supply roll and a separation roll at a constant pressure when the sheet is rolled. Then, when the smooth sheet is separated and conveyed, a pressing force that is about 30 times that of normal plain paper is required. As a method for eliminating such close contact with a smooth sheet in advance, a technique for blowing air from the side surface of stacked sheets has been proposed (see, for example, Patent Document 1). According to said technique, a big effect can be raised to cancellation | release of the adhesive force in a smooth sheet.

However, in the above method, since it is necessary to send out a sheet after a predetermined time from the start of air blowing, this air blowing time (blow time) before feeding is added to the processing time of one sheet. . For this reason, the processing time per sheet increases, resulting in deterioration of productivity. In particular, in a method in which a plurality of paper feeding devices are used while being switched (switched), the air blowing time before paper feeding is required every time switching is performed, and thus a problem that processing time further increases occurs. .
JP-A-11-005643 (FIG. 1, pages 4-12)

  In consideration of the above-described facts, an object of the present invention is to provide a sheet feeding apparatus that has excellent transportability and high productivity.

The sheet supply apparatus according to claim 1, a sheet storage unit that stores sheets, a sheet supply unit that sequentially supplies sheets stored in the sheet storage unit to the next process, and a sheet stored in the sheet storage unit. If the next sheet supply is started within a predetermined time after the sheet supply by the sheet supply means is completed , the air spray means is continuously operated with the same spray amount. And a control means for operating the air spraying means for a predetermined time with the same spraying amount if the next sheet supply is not started within the predetermined time .

In the invention of the above configuration , when the next sheet supply is started within a predetermined time after the sheet supply by the sheet supply unit is completed , the air spraying unit is operated with the same spraying amount to perform continuous processing. Since the air blowing before supply can be omitted while releasing the adhesion between the second and subsequent sheets , productivity during continuous processing is improved.

more than

  The sheet supply apparatus according to claim 2 is characterized in that the predetermined time for operating the air blowing means after the sheet supply is completed is variable.

  In the invention with the above configuration, an optimal air blowing time can be set in accordance with the surface physical properties of the sheet to be supplied and the processing capacity per unit time.

  The sheet supply apparatus according to claim 3, wherein a plurality of sheet storage units that store sheets, a sheet supply unit provided for each of the sheet storage units, and an air spray provided for each of the plurality of sheet storage units And a control means for operating the air blowing means provided in the one sheet storage means for a predetermined time after switching the sheet supply from one sheet storage means to the other sheet storage means. It is characterized by that.

  In the invention having the above-described configuration, when the plurality of sheet storage units are switched and operated, air is blown to the storage unit that has finished supplying the sheet, so that the air before supply is switched when the sheet storage unit is switched again and processed. Since spraying can be omitted, productivity during continuous processing is improved.

  The sheet supply apparatus according to claim 4 is characterized in that the predetermined time for operating the air blowing means is equal to or longer than the sheet supply interval at the time of continuous sheet supply.

  In the invention having the above-described configuration, when the sheet accommodating means is switched twice or more and continuously processed, the air blowing before supply is omitted in order to resume the operation of the first sheet accommodating means within a predetermined time for operating the air blowing means. This improves productivity during continuous processing.

  6. The sheet supply apparatus according to claim 5, wherein when the air blowing means of the sheet storing means is in operation at the start of sheet supply, the sheet supply starts, and when the air blowing means is stopped, the air blowing is started. And the sheet supply is started at a predetermined timing.

  In the invention having the above-described configuration, when the plurality of sheet storage units are switched and operated, the sheet storage unit can be smoothly switched without impairing the sheet transportability.

  According to a sixth aspect of the present invention, there is provided a sheet supply device that operates an air blowing means provided in the other sheet storage means before switching the sheet supply from one sheet storage means to the other sheet storage means.

  In the invention with the above configuration, when the plurality of sheet storage units are switched and operated, the air blowing unit is operated in advance before switching, so that the sheet storage unit can be smoothly switched.

  The sheet supply apparatus according to claim 7, when the sheet supply remaining number from one sheet storage unit becomes a predetermined number or less before switching the sheet supply from one sheet storage unit to the other sheet storage unit, The air blowing means provided in the other sheet storage means is operated.

  In the invention having the above-described configuration, when the plurality of sheet storage units are switched and operated, the air blowing unit is operated in advance before the switching operation starts, so that the sheet storage unit can be smoothly switched.

  Since the present invention has the above-described configuration, a sheet feeding apparatus having excellent transportability and high productivity can be obtained.

  FIG. 1 shows an image forming apparatus using a sheet feeding apparatus according to a first embodiment of the present invention.

  As shown in FIG. 1, the image forming apparatus 21 includes an image reading device 23, a receiving unit 29 connected to an external device (such as a personal computer) 25 through a communication line 27, and an image document based on image information from the receiving unit 29. An image recording control unit 33 for controlling the image capturing device 31, a cylindrical image carrier 35 on which an electrostatic latent image is written by the image writing device 31, and a circumferential direction of the image carrier 35. A charger 37, a developing device 39, a cleaner 41, a transfer roller 43 for transferring an image formed on the image carrier 35 to a paper, a fixing device 45 for fixing the image transferred to the paper, and a paper from the fixing device 45 to the paper. A sheet discharge roller 47 for discharging the sheet, a discharge tray 49 for stacking sheets discharged by the discharge roller 47, and a sheet transport unit 51 between the image carrier 35 and the transfer roller 43. And a supplying sheet feeding apparatus 10.

  When the receiving unit 29 receives an image signal via the communication line 27 from the image reading device 23 or the external device 25, the image recording control unit 33 controls the image writing device 31 according to the received image signal, and the image signal is converted into an image. For example, image light composed of laser light is emitted.

  The image carrier 35 whose surface is charged by the charger 37 forms an invisible electrostatic image on the surface by the image light from the image writing device 31. The electrostatic image is developed with toner by the developing device 39 to become a toner image, and a toner image is formed on the surface of the image carrier 35.

  The sheets P stored in the sheet tray 12 of the sheet supply apparatus 10 are conveyed one by one to the sheet feeding unit 60 one by one from the top by the supply roller 16, pass through the sheet conveying unit 51, and are transferred to the image carrier 35 by the transfer roller 43. Contact with the pressure of. At this time, the toner image on the surface of the image carrier 35 is transferred to the paper P passing between the image carrier 35 and the transfer roller 43. The toner image transferred to the paper P is fixed by the fixing device 45, and the paper P passes through the discharge roller 47 and is discharged to the discharge tray 49 to become a printout image.

  Here, the paper P stored in the paper tray 12 of the sheet supply apparatus 10 is blown to prevent so-called multi-feeding, in which a plurality of paper P is supplied in close contact when being fed out from the paper feed tray 12 one by one. Wind is sent from the side of the paper P by the fan 14 to release the close contact between the papers P. The blower fan 14 is on / off controlled by the control device 18.

  FIG. 2 shows a sheet feeding apparatus according to the first embodiment of the present invention.

  As shown in FIG. 2, the sheet supply apparatus 10 includes a paper tray 12, a blower fan 14, and a supply roller 16, and the paper P stored in the paper tray 12 is viewed from above by a supply roller 16 driven by a delivery motor (not shown). The sheets are conveyed one by one in the direction of the black arrow. The supply roller 16 is supported by a movable shaft (not shown) so as to be swingable in the vertical direction, and conveys the uppermost paper P with a constant pressure corresponding to the fluctuation of the height of the paper P. Further, the bottom plate of the paper tray 12 is provided with an elevating mechanism (not shown), and the height of the uppermost paper P is kept constant even when the paper P is consumed and the bundle of the paper P becomes thin.

  The blower fan 14 sends air in the direction of the white arrow from the outside into the paper tray 12 to generate a gap between the sheets P and release the close contact between the sheets P. As a result, it is possible to prevent so-called double feeding in which a plurality of sheets P are supplied in close contact.

  At this time, as shown in FIG. 2, a plurality of sheet supply apparatuses 10 are provided, and the interval between sheets can be increased by switching and using.

  FIG. 3 shows the operation timing of the sheet feeding apparatus according to the first embodiment of the present invention.

  When the image forming apparatus 21 is activated and a sheet feed start signal is sent to the sheet supply apparatus 10, conventionally, as shown in FIG. 4, the blower fan 14 is first activated by the control device 18 that has received the sheet feed start signal (1). Then, the wind continues to be sent until the predetermined spraying time T1 elapses to release the contact of the paper P, and then the feed motor is operated to drive the supply roller 16 to feed the paper P. When the paper P is sent out, the control device 18 stops the blower fan 14.

  Therefore, even when the paper feed start signal is continuously sent as shown in FIG. 4, the control device 18 that has received the paper feed start signal (2) newly drives the blower fan 14 and the predetermined blowing time T1 has elapsed. In order to release the adhesion of the paper P by continuing to send the wind until the sheet P is processed, a predetermined spraying time T1 is consumed every time one sheet P is processed, resulting in a time loss, resulting in a decrease in the number of processed sheets per unit time, that is, production. It was causing a decline in sex.

  In this embodiment, as shown in FIG. 3, after the sheet P1 is processed by the paper feed start signal (1), the blower fan 14 is continuously driven until a predetermined post-blowing time T2 elapses. If the control device 18 receives the paper feed start signal (2) until the predetermined post-blowing time T2 elapses, the blower fan 14 is continuously operating, so the second and subsequent sheets have the predetermined spraying time T1. Do not need.

  For this reason, when the paper feed start signal (2) is continuously received, the spraying time T1 before processing the second paper P is omitted, and the transport of the paper P directly starts. As a result, the time loss during continuous processing, which is a problem in the conventional example of FIG. 4, that is, the processing time during continuous processing is shortened by a predetermined spraying time T1.

  As a result, the number of processed sheets per unit time during continuous processing increases and productivity is improved. Further, since the blower fan 14 is driven, so-called multi-feeding in which a plurality of sheets P are supplied in close contact with each other can be prevented.

  Further, the predetermined post-spraying time T2 can be made variable according to the surface physical properties of the supplied sheet and the processing capacity per unit time. Thereby, it is possible to set the optimum post spraying time T2 in accordance with the above various conditions.

  FIG. 5 shows the operation timing of the sheet feeding apparatus according to the second embodiment of the present invention.

  When the image forming apparatus 21 is activated and a paper feed start signal (1) is sent to one of the plurality of sheet supply apparatuses 10, conventionally, the control device 18 that has received the paper feed start signal (1) as shown in FIG. As a result, the blower fan 14 is actuated first, and the wind continues to be sent until the predetermined blowing time T1 elapses to release the close contact of the paper P. Thereafter, the feed motor is operated to drive the supply roller 16 and feed the paper P. When the paper P is sent out, the control device 18 stops the blower fan 14.

  Next, when the sheet feeding start signal (2) is sent to the other sheet supply device 10 ′, the blowing fan 14 ′ continues to send the wind until the predetermined blowing time T1 elapses to release the adhesion of the paper P, and thereafter The feed motor 16 'is driven to drive the supply roller 16' to feed the paper P. After this, when the paper feed start signal (3) is sent to the first sheet supply apparatus 10, the blower fan 14 is operated again until a predetermined spraying time T1 elapses.

  That is, every time the sheet supply apparatus 10 is switched and used, the blower fan 14 is operated until a predetermined spraying time T1 elapses. Therefore, every time the sheet supply apparatus 10 is switched, the predetermined spraying time T1 is consumed and time is lost. As a result, the number of processed sheets per unit time is reduced, that is, productivity is reduced.

  In this embodiment, as shown in FIG. 5, the blower fan 14 is driven until a predetermined post-spraying time T2 elapses after the sheet P1 is processed by the first sheet supply device 10 by the paper feed start signal (1). to continue. When the control device 18 ′ receives the sheet feeding start signal (2) of the other sheet supply device 10 ′, the blower fan 14 ′ is also operated until the predetermined blowing time T1 elapses. T1 is the same as in the conventional example.

  Here, when the paper feed start signal (3) is sent again to the first sheet supply apparatus 10, until the predetermined post spray time T2 elapses after the paper feed start signal (1), Since the blower fan 14 is in operation, there is no need to wait until a predetermined blowing time T1 has elapsed. That is, every time the sheet supply apparatus 10 is switched and used, the time loss that has occurred because the blower fan 14 is operated until the predetermined blowing time T1 elapses does not occur.

  For this reason, in the present embodiment, when the plurality of sheet supply apparatuses 10 are continuously used by switching, the predetermined spraying time T1 is not required from the second switching (switching), and therefore the continuous switching process is performed by the amount corresponding to T1. The processing time is shortened.

  At this time, by setting the post-spraying time T2 to be longer than the paper P delivery interval during continuous processing (that is, by setting T2 to 1 second or more if there is a processing capacity of 60 sheets per minute) When receiving a paper feed start signal at the time of switching (switching), since the blower fan 14 is operating during continuous processing, the processing can be resumed without waiting for a predetermined blowing time T1 before processing, and is more effective. In addition, the processing time during the continuous switching process is shortened.

  In addition, after the sheet supply device 10 is switched, if the blower fan 14 is in operation when the supply of the paper P is started, the supply of the paper P is started, and if the blower fan 14 is stopped, the air blowing is started. By setting so as to start the supply of the paper P at this timing, it is possible to minimize the time loss when the sheet supply apparatus 10 is switched.

  FIG. 7 shows the operation timing of the sheet feeding apparatus according to the third embodiment of the present invention.

  When the image forming apparatus 21 is activated and a paper feed start signal (1) is sent to one of the plurality of sheet supply apparatuses 10, the blower fan 14 is first activated by the control device 18 that has received the paper feed start signal (1). The wind continues to be sent until the predetermined spraying time T1 elapses to release the contact of the paper P. Thereafter, the feed motor is operated to drive the supply roller 16 and feed the paper P. The control device 18 stops the blower fan 14 when the paper P is sent out and the job being processed (for example, printing processing of 10 processed sheets) is completed.

  At this time, when a job to be processed is switched to another sheet supply apparatus 10 ′ at the same time as the job being processed and a job to be processed is set, the time loss at the time of switching cannot be reduced in the conventional example or the above-described embodiment ( This is because the predetermined spraying time T1 before processing cannot be omitted).

  However, before the job being processed in the first sheet supply apparatus 10 (for example, the printing process of 10 processed sheets) is completed (for example, when the remaining number of processed sheets is 1), the sheet supply apparatus to be switched to. If the setting is made so that the 10 ′ blower fan 14 ′ is operated, the job being processed in the first sheet supply apparatus 10 is completed, and the sheet supply apparatus 10 receives the sheet supply start signal (2) and supplies the sheet. At the time of switching to the apparatus 10 ′, since the blower fan 14 ′ of the sheet supply apparatus 10 ′ that is the switching destination is already in operation, the time loss at the time of switching can be efficiently reduced. At this time, it is not necessary to set the rear blowing time T2 as in the first and second embodiments (because the blower fan 14 'is operating at the time of switching).

  Furthermore, by setting the timing for operating the blower fan 14 ′ of the sheet supply apparatus 10 ′ as the switching destination so that the blowing operation is performed longer than the predetermined blowing time T1 before processing, the time loss at the time of switching is set. Therefore, continuous processing can be performed more efficiently. That is, the time loss at the time of switching can be eliminated by setting so that the switching is performed after the lapse of time T1 or more after the operation of the blower fan 14 'of the sheet supply apparatus 10' as the switching destination.

  The above embodiment is an example of the image forming apparatus, but the present invention is not limited to the image forming apparatus, and can be applied to other devices for conveying a sheet, such as a cutting machine or a press machine.

1 is a cross-sectional view illustrating an image forming apparatus according to a first embodiment of the present invention. It is a perspective view which shows the sheet supply apparatus which concerns on the 1st form of this invention. It is a figure which shows operation | movement of the sheet supply apparatus which concerns on the 1st form of this invention. It is a figure which shows operation | movement of the conventional sheet supply apparatus. It is a figure which shows operation | movement of the sheet supply apparatus which concerns on the 2nd form of this invention. It is a figure which shows operation | movement of the conventional sheet supply apparatus. It is a figure which shows operation | movement of the sheet supply apparatus which concerns on the 3rd form of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sheet supply apparatus 12 Paper feed tray 14 Blower fan 16 Supply roller 18 Control apparatus 21 Image forming apparatus

Claims (7)

Sheet storage means for storing the sheet;
Sheet supply means for sequentially supplying the sheets stored in the sheet storage means to the next process;
Air blowing means for blowing air against the sheet accommodated in the sheet accommodating means;
After the sheet supply by the sheet supply means is completed , if the next sheet supply is started within a predetermined time, the air blowing means is continuously operated with the same blowing amount,
And a control unit that operates the air spraying unit for a predetermined time with the same spraying amount if the next sheet supply is not started within the predetermined time .
2. The sheet feeding apparatus according to claim 1, wherein the predetermined time during which the air blowing means is operated after the sheet feeding is finished is variable.
A plurality of sheet storing means for storing sheets;
Sheet supply means provided for each sheet storage means;
An air blowing means provided for each of the plurality of sheet containing means,
And a control means for operating an air blowing means provided in one of the sheet storage means for a predetermined time after the sheet supply is switched from one sheet storage means to the other sheet storage means. Feeding device.
The sheet supply apparatus according to claim 3, wherein the predetermined time for operating the air blowing means is set to be equal to or longer than a sheet supply interval at the time of continuous sheet supply.
If the air blowing means of the sheet storage means is in operation at the start of sheet supply, start the sheet supply,
It said air blowing means starts blowing air if stopped, the sheet feeding apparatus according to claim 3 or claim 4, characterized in that to start the supply of the sheets at a predetermined timing.
Any one of claims 3 to 5, characterized in that to operate the air blowing means provided on the other sheet container before switching sheet feeding from one of the sheet containing means to the other sheet container The sheet supply apparatus according to 1.
Before switching the sheet supply from one sheet storage means to the other sheet storage means, when the remaining number of sheets supplied from one sheet storage means falls below a predetermined number, the air blowing provided on the other sheet storage means The sheet feeding apparatus according to any one of claims 3 to 6, wherein the means is operated.

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