JP3885862B2 - Sheet supply apparatus and image forming apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet holder that accommodates a sheet used in an image forming apparatus.
[0002]
[Prior art]
As a conventional image forming apparatus, for example, an image forming apparatus in which a toner image formed on a photoreceptor is transferred to a sheet (paper) by a transfer device and then fixed by a fixing device is known.
[0003]
In such an image forming apparatus, for example, a plurality of sheet feeding trays are provided in the sheet feeding unit of the apparatus main body, and sheets of different sizes are accommodated in these sheet feeding trays. Can be printed. Each of these paper feed trays is provided with means for transmitting information on the size of the stored paper to the control device of the apparatus main body, and includes information such as the document size and the enlargement / reduction ratio specified by the operator. Accordingly, a sheet of an arbitrary size can be sent out from the sheet feeding unit.
[0004]
In addition to feeding from the paper feed tray as described above, a manual feed tray is arranged so that postcards that cannot be stored in the paper feed tray, OHP sheets, and other irregularly shaped paper can be supplied. Yes. Such a manual feed tray is also known in which information on the size of the paper to be placed can be obtained by the position of the side guide that regulates the side edge of the paper (for example, Japanese Patent Laid-open No. Hei. No. 8-328429).
[0005]
By the way, in this type of image forming apparatus, normally, from the viewpoint of ensuring productivity, the image forming process for plain paper that is used most frequently as a sheet is standard, and based on this, a transfer device and a fixing device are used. In this case, the sheet conveyance speed or the like is set.
[0006]
Therefore, for example, when using a thick paper such as a postcard, an OHP sheet, a coated paper, or the like, there is no problem in transferring the toner image onto the sheet with the transfer device. Since it is larger than paper, the amount of fixing heat is insufficient, and the toner constituting the toner image may remain on the special sheet without being heated and melted, resulting in poor fixing.
[0007]
Therefore, when using a sheet having a large heat capacity, it is necessary to increase the amount of fixing heat to sufficiently heat the toner. Conventionally, the sheet conveyance speed (fixing speed) in the fixing device is decreased to reduce the heating time. The method of securing is used.
Conventionally, when using a sheet having such a large heat capacity, the operator inputs or designates the sheet type, and the image forming process is changed based on this.
[0008]
[Problems to be solved by the invention]
However, in such a mode, there is a possibility that the operator may forget or miss the input or designation of the sheet type, and in that case, it is impossible to prevent the occurrence of fixing failure. Issues were seen.
[0009]
In JP-A-11-227953, a sheet is stored in a sheet storage magazine, an identification member that selectively reflects light is attached to the sheet storage magazine, and an optical sensor is provided on the apparatus main body side. Thus, a technique has been proposed in which the type of sheet to be accommodated is identified.
[0010]
However, in such a technique, there is a technical problem that the configuration of the apparatus becomes complicated and the cost increases because a new optical sensor has to be provided.
[0011]
The present invention has been made in order to solve the above technical problem, and is a sheet supply device capable of obtaining information on the type of a set sheet with a simple configuration, and an image forming apparatus using the same. Is to provide.
[0012]
[Means for Solving the Problems]
That is, according to the present invention, as shown in FIG. 1, a set tray 2 on which a sheet S can be directly placed, and a set tray 2 that is detachably set, accommodates the sheet S therein, and is a type of the sheet S. Correspondingly, the sheet holder 1 whose shape can be changed in a direction orthogonal to the sheet feeding direction, the size of the sheet S directly placed on the set tray 2 and the shape change of the sheet holder 1 set on the set tray 2. And a discriminating unit for discriminating the size of the sheet S placed directly on the set tray 2 and the type of the sheet S stored in the sheet holder 1 based on the detection result of the detecting unit 3 4.
[0013]
In such technical means, sets as the Tray 2, the sheet S is available directly placed, and may be any settable sheet holder 1 is detachably normal paper feed tray or manual feed tray or the like as appropriate You can choose.
[0014]
The length of the sheet holder 1 in the direction orthogonal to the sheet feeding direction may be appropriately selected as long as it is set to be different depending on the type of the sheet S to be accommodated. From the viewpoint of preventing erroneous detection, it is preferable to set the length different from the direction length orthogonal to the sheet conveying direction of the standard size document.
Here, the type of sheet S includes, for example, the size (size), thickness, presence / absence of a coating layer, paper quality, and the like of the sheet S.
[0015]
Further, from the viewpoint of surely preventing the above-described erroneous detection, switching for switching the processing of the determination unit 4 between when the sheet holder 1 is set on the set tray 2 and when the sheet S is set. Preferably, means 5 are provided.
[0016]
From the viewpoint of always setting the sheet holder 1 at the same position on the set tray 2, the set tray 2 is preferably provided with an engaging member that engages with the sheet holder 1.
[0017]
Further, the sheet supply apparatus according to the present invention is preferably applied to an image forming apparatus including an image forming unit 6 that forms an image on a sheet supplied from the sheet supply apparatus. It is preferable that a control unit 7 for controlling the image forming process of the image forming unit 6 based on the determination result of the determining unit 4 is provided.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 2 shows an embodiment of an image forming apparatus (color image forming apparatus) in which the sheet holder according to the present invention is used.
In the figure, reference numeral 11 denotes a photosensitive drum that rotates in the direction of the arrow, 12 denotes a charger such as a corotron that precharges the photosensitive drum 11, and 13 denotes an image writing device (ROS) such as a laser scanning device. The surface of the photosensitive drum 11 is irradiated with a laser beam modulated by a laser drive signal generated for each component. The ROS 13 writes a digital image input from the image processing unit (IPS) 15 as an electrostatic latent image on the photosensitive drum 11 in accordance with an image output instruction input from a host device (not shown). Reference numeral 14 denotes a rotary type developing device equipped with developing units corresponding to Y, M, C, and K colors. The electrostatic latent image formed on the photosensitive drum 11 is developed to produce each color component toner image. It comes to form. Reference numeral 16 denotes a drum cleaner that removes residual toner on the photosensitive drum 11, and 17 denotes an intermediate transfer belt disposed so as to be in contact with the surface of the photosensitive drum 11, which is stretched around a plurality of rolls. And turn in the direction of the arrow. Further, a transfer roll 18 is disposed at a portion (primary transfer position) of the intermediate transfer belt 17 facing the photosensitive drum 11, and a voltage having a polarity opposite to the toner charging polarity is applied to the transfer roll 18. Thus, the toner image on the photosensitive drum 11 is electrostatically attracted to the intermediate transfer belt 17.
[0019]
Furthermore, a secondary transfer device 19 including a secondary transfer roll and a counter roll is disposed at the secondary transfer position of the intermediate transfer belt 17 facing the conveyance path of the sheet P as a sheet. On the other hand, the electrostatic image is transferred. Thereafter, the sheet P on which the unfixed image is transferred is thermally fixed by the fixing device 20.
Reference numeral 50 denotes a control unit that controls the supply and conveyance of the paper P in addition to various controls during image formation.
[0020]
Next, the paper transport system in the present embodiment will be described. The sheet transport system includes sheet trays 31 to 34 that are sheet stacking sections on which sheets P are stacked, and a manual feed tray 35 that supplies sheets from outside the apparatus. Furthermore, the upper part of each paper tray 31-34 has the drawing roll 36 which contacts the picked-up paper P and picks up from an upper surface, and also supplies and rolls the paper one sheet at a time further downstream. The paper handling unit 37 is provided on the downstream side thereof, and a takeaway roll 38 is provided on the downstream side thereof. The takeaway roll 38 also has a function as a transport roll for simply transporting the paper to the paper path when the paper P is supplied from the lower paper trays 32 to 34. Also, a nudger roll 48 that contacts the stacked paper P and picks up from the upper surface is provided at the upper part of the manual feed tray 35, and a takeaway roll 38 is provided on the downstream side thereof.
[0021]
The paper path 40 on the downstream side of the takeaway roll 38 has a registration roll (registration roll) 39 for conveying the paper to the secondary transfer device 19 in accordance with the timing of image formation. After the positioning is stopped at 39, the unfixed image is transferred to the paper P. Further, a conveyance belt 41 is provided on the downstream side, and the sheet P is conveyed to the fixing device 20 by the conveyance belt 41.
In particular, in this embodiment, when the duplex mode is selected, a sheet return transport mechanism is provided for inverting the sheet that has been fixed on one side by the fixing device 20 and returning it to the secondary transfer position again. The paper return transport mechanism is provided with a paper branch path 44 that branches downward with respect to the paper discharge path 43 from the fixing device 20, and a paper reversing path 45 extends further downward on the paper branch path 44. In addition, a sheet return path 46 that returns from the sheet reversal path 45 to the sheet path 40 before the secondary transfer position is connected in communication.
The paper branching path 44, the paper reversing path 45, and the paper returning path 46 are provided with an appropriate number of transport rolls 47. In particular, the transport roll 47 provided in the paper reverse path 45 rotates forward and reverse at appropriate timing. It is like that.
Further, a sheet switching gate (not shown) is provided between the sheet discharge path 43 and the sheet branch path 44 and between the sheet branch path 44, the sheet reversing path 45, and the sheet return path 46. The paper path is appropriately switched and selected according to the selected mode.
[0022]
Further, as shown in FIG. 3, the manual feed tray 35 has a side guide 61 disposed on the manual feed tray 35, and a guide rail 62 and a sensor holding frame 63 are provided on the back surface of the tray so as to correspond to the side guide 61. It has the structure to arrange. In the manual feed tray 35, a fixed-side guide member 64 is disposed on one side, and a side guide 61 is movably provided along the guide groove 65 on the other side. Then, one side surface of the paper P (not shown) set on the manual feed tray 35 is brought into contact with the fixed-side guide member 64, and the guide plate 66 of the side guide 61 is pressed against the other side of the paper P, thereby Positioning is performed in a direction (width direction) orthogonal to the conveyance direction of P. The nudger roll 48 is arranged on the fixed guide member 64 side.
[0023]
As shown in FIGS. 3 to 5 , the sensor holding frame 63 disposed corresponding to the side guide 61 has an insertion pin 68 protruding from the side guide 61 through a guide groove 65 provided in the tray bottom plate 67. The insertion pin 68 is inserted into an insertion hole 69 provided in the sensor holding frame 63 and attached thereto. Then, the sensor holding frame 63 is moved by following the movement of moving the side guide 61 in the width direction of the manual feed tray 35, and slides with respect to the resistance member 70 provided at a fixed position inside the sensor holding frame 63. The member 71 is slid, and the sheet size is detected using the resistance value information in the resistance member 70. A slide member 71 provided to be slidable with respect to the resistance member 70 is arranged with a pin member 72 projecting from the upper portion, and the pin member 72 is pressed against the guide rail 62 and slid.
[0024]
In order to press the slide member 71 against the guide rail 62, a swing arm 73 is arranged, the swing arm 73 is swingably provided via a support shaft 74, and the swing arm 73 is supported by a spring 75. It urges clockwise through 74. Further, a long hole 76 is disposed at the tip of the swing arm 73, and the pin member 72 of the slide member 71 is inserted into the long hole 76 so that the slide member 71 is located on the downstream side in the sheet conveying direction. It constitutes means for energizing it. Therefore, by configuring the support means for the slide member 71 via the swing arm 73 urged by the spring 75, the pin member 72 of the slide member 71 is constantly pressed against the guide rail 62. Therefore, the movement of positioning the slide member 71 by following the movement of the side guide 61 can be performed accurately.
[0025]
In a state where, for example, a large-size sheet P is set on the manual feed tray 35, the side guide 61 is stopped at a position far away from the fixed-side guide member 64 as shown in FIG. Since the slide member 71 is in a position close to the end of the resistance member 70, the resistance value output from the slide member 71 is a very small value. On the other hand, when a small-size sheet is set on the manual feed tray 35, the side guide 61 is moved to a position close to the fixed-side guide member 64 to position the sheet P, and thus obtained from the resistance member 70. The resistance value is a very large value. With this configuration, the size of the paper P can be determined by the size of the resistance value.
[0026]
Further, in the image forming apparatus according to the present embodiment, the paper P can be directly placed on the manual feed tray 35 described above, and a paper holder (sheet holder) in which the paper P is accommodated can be placed. Yes.
In the present embodiment, the paper holder 80 includes a housing 81 in which a paper P (not shown) is accommodated, as shown in FIGS.
Further, a delivery opening 81a for delivering the paper P is formed on the side surface of the housing 81, and on the upper surface of the housing 81 near the delivery opening 81a, the nudger roll 48 and the housing 81 are provided. A take-out opening 81b for contacting the paper P is formed. Here, the opening on the lower side of the delivery opening 81a, the high friction member 82 made of a rubber-based material is provided, the delivery opening 81a is corresponding to one or more two less than a thickness of a postcard It is set to height.
A lifter 83 is provided at the bottom of the housing 81. The lifter 83 has a substantially central portion as a swing shaft and extends toward the delivery opening 81a. The lifter 83 can be swung by a lift mechanism 91 (see FIG. 8) provided on the manual feed tray 35 described later.
[0027]
Further, the housing 81, the slide mechanism 84 is provided for varying the length of the paper holder 80 in the direction (hereinafter referred to simply as the width direction) perpendicular to the delivery direction of the sheet P delivered.
The slide mechanism 84 includes a slide plate 85 disposed on the upper surface of the housing 81 and a fastener 86 that engages the housing 81 so that the slide plate 85 is movable in the width direction. Further, notches 87, 88, 89 having a triangular cross section are formed on one end side (right side in the figure) of the slide plate 85 in the moving direction, and on the opposite side of the upper surface of the housing 81 from the one end side. A click 90 is provided to engage with the notches 87 to 89 and latch the slide plate 85.
[0028]
By doing so, in the present embodiment, as shown in FIGS. 7A to 7C, the length in the width direction of the paper holder 80 can be varied in three stages W1, W2, and W3. It has become.
[0029]
In addition, a substantially rectangular display window 85 a is opened at a substantially central portion of the slide plate 85. In the present embodiment, the width in the width direction of the paper holder 80 is made different depending on the type of the paper P accommodated in the housing 81. At that time, the display window 85a has a width thereof. The type of paper P corresponding to the length in the direction is displayed, and set errors can be prevented.
In the image forming apparatus according to the present embodiment, for example, a paper P that needs to adopt an image forming process different from the image forming process of plain paper, such as a postcard having a coat layer for an ink jet printer provided on the surface. It is accommodated in the paper holder 80.
[0030]
Further, the width direction lengths W1, W2, and W3 of the paper holder 80 described above are the same as those of standard-size originals (A3, A4, A5, B4, and B5) placed on the manual feed tray 35, as shown in FIG. A size different from the width direction length is set.
In the figure, reference numeral 91 is a lift mechanism provided corresponding to the lifter 83 of the paper holder 80, and 92 is a detection sensor for detecting the placement of the paper P or the paper holder 80.
[0031]
FIG. 9 shows a block diagram of the control unit 50.
In the figure, an input signal from the operation panel 93 and a size signal from the manual feed tray 35 are taken into the CPU 52 via the input interface 51. Next, the CPU 52 executes a control program stored in advance in the ROM 53. After appropriately performing data processing with the RAM 54, control signals are sent to the photosensitive drum 11, ROS 13, rotary developing device 14, intermediate transfer belt 17, transfer roll 18, secondary transfer device 19 and the like via the output interface 55. Is sent out.
[0032]
In the image forming apparatus according to the present embodiment, as shown in FIG. 10, when the manual feed tray 35 is not used, that is, when the paper P is conveyed from the paper trays 31 to 34, the paper holder 80 is placed on the manual feed tray 35. Is not installed, that is, when the size signal from the manual feed tray 35 has a value different from the widths W1, W2, and W3 in the width direction, it is optimal for the normal image forming mode, that is, the plain paper. The set image forming process is executed.
On the other hand, when the paper holder 80 is mounted on the manual feed tray 35, that is, when the size signal from the manual feed tray 35 has a value in the width direction of W1, W2, or W3, special image formation is performed. An image forming process optimally set for each type of paper corresponding to the mode, that is, W1 to W3 is executed.
[0033]
Specifically, for example, when a postcard for an ink jet printer is used as the paper P, the fixing speed of the fixing device 20 is decreased and the conveying speed of the conveying belt 41 is secured in order to secure the amount of fixing heat. To lower.
Further, since the postcard is accommodated in the paper holder 80, the registration in the width direction of the paper P is shifted by the thickness of the paper holder 80, but the image on the photosensitive drum 11 by the ROS 13 is correspondingly shifted. The writing position is shifted to prevent image shift.
[0034]
Further, for example, when a paper P having a length in the transport direction longer than the distance between the secondary transfer position and the fixing device 20 is used, when the leading edge of the paper P enters the fixing device 20. Since the rear end of the paper P has not yet passed through the secondary transfer position, if only the fixing speed of the fixing device 20 and the transport speed of the transport belt 41 are reduced, the paper P forms a large loop, There is a possibility that unfixed toner on the paper P is rubbed against the peripheral members to cause smudge, or the paper P is wrinkled during fixing. In such a case, in addition to the above, the rotational speed of the photosensitive drum 11 and the rotational speed of the intermediate transfer belt 17 are reduced, and the switching timing of the rotary developing device 14 is changed accordingly.
Furthermore, when it is necessary to adjust the transfer bias depending on the type of paper P, the transfer bias by the secondary transfer device 19 is adjusted.
These settings are set in advance corresponding to the type of the paper P, that is, the widths W1, W2, and W3 of the paper holder 80, and are stored in the ROM 53.
[0035]
In the present embodiment, the attachment of the paper holder 80 and the type of the paper P accommodated therein are automatically detected, and the image forming process is optimally controlled according to the detected paper type. A good image can be obtained without causing defects.
[0036]
Further, by changing the length in the width direction of the paper holder 80 in accordance with the type of the paper P accommodated in the paper holder 80, the type of the paper P is used by the side guide 61 that has been conventionally used. Can be detected without complicating the device configuration.
[0037]
In the present embodiment, whether the paper P is placed on the manual tray 35 or the paper holder 80 is automatically determined based on the size signal from the manual tray 35. For example, as shown in FIG. 11, when the paper holder use mode is designated on the operation panel 93 (see FIG. 9), the above-described special image forming mode may be executed. .
[0038]
Further, as shown in FIG. 12, a movable slide lid 94 that is urged upward is provided in the delivery opening 81a of the paper holder 80, and the slide lid 94 is moved downward during mounting. If the slide lid 94 is moved upward by an urging force and closed at the time of detachment, it is possible to prevent intrusion of dust or moisture.
[0039]
Further, as shown in FIG. 12, a rail 95 is provided along the paper discharge / feeding direction below the bottom surface of the paper holder 80, and the rail 95 engages with a corresponding portion of the manual feed tray 35 shown in FIG. If 96 (see FIG. 8) is provided, the paper holder 80 can always be mounted at the same position on the manual feed tray 35.
[0040]
Furthermore, in the present embodiment, the width in the width direction of the paper holder 80 is made different depending on the type of the paper P using the slide plate 85, but the present invention is not limited to this. As shown in FIGS. 13A to 13C, the length of the housing 81 in the width direction itself may be varied. However, in this case, it is necessary to provide the partition member 97 according to the paper P accommodated inside.
[0041]
【The invention's effect】
As described above, according to the present invention, the size of the sheet placed directly on the set tray and the shape change in the direction perpendicular to the sheet feeding direction of the sheet holder set on the set tray are detected, and this is detected. Since the size of the sheet directly placed on the set tray and the type of the sheet stored in the sheet holder are determined based on the information, information on the type of the set sheet can be obtained with a simple configuration. .
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining an outline of a sheet feeding apparatus according to the present invention and an image forming apparatus using the same.
FIG. 2 is a schematic configuration diagram showing an outline of an embodiment of an image forming apparatus using a sheet holder according to the present invention.
FIG. 3 is an explanatory diagram illustrating a configuration of a manual feed tray and a size detection device.
FIG. 4 is a side view showing a configuration of a side guide and a size detection device.
FIG. 5 is a plan view showing a configuration of a size detection device.
6A is a plan view showing a configuration of a paper holder, and FIG. 6B is a side view thereof.
7A to 7C are schematic views showing the relationship between the position of the slide plate and the width direction length of the paper holder.
FIG. 8 is a schematic diagram showing a relationship between a manual feed tray and a width direction of a paper holder.
FIG. 9 is a block diagram of a control unit.
FIG. 10 is a flowchart illustrating a control example of a control unit.
FIG. 11 is a flowchart showing another control example of the control unit.
12A is a plan view showing another configuration example of the paper holder, and FIG. 12B is a side view thereof.
FIGS. 13A to 13C are schematic views showing still another configuration example of the paper holder.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Sheet holder, 2 ... Set tray, S ... Sheet, 35 ... Manual feed tray, 50 ... Control part, 61 ... Side guide, 64 ... Fixed side guide member, 70 ... Resistance member, 80 ... Paper holder, 81 ... Housing, 81a ... opening for delivery , 82 ... high friction member, 84 ... slide mechanism, 85 ... slide plate, 85a ... display window, 87-89 ... notch, 90 ... click, 95 ... rail, 96 ... groove, 97 ... partition Element

Claims (4)

A set tray on which sheets can be placed directly ;
A sheet holder that is detachably set in the set tray, accommodates a sheet therein, and has a shape changeable in a direction perpendicular to the sheet feeding direction according to the type of the sheet;
Detection means for detecting the size of the sheet placed directly on the set tray and the shape change of the sheet holder set on the set tray ;
A sheet feeding apparatus comprising: a discriminating unit that discriminates a size of a sheet directly placed on a set tray and a type of a sheet stored in the sheet holder based on a detection result of the detecting unit. The sheet feeding apparatus according to claim 1, wherein
A sheet supply apparatus comprising: a switching unit that switches processing of the determination unit between when a sheet holder is set on the set tray and when a sheet is set. The sheet feeding apparatus according to claim 1, wherein
The sheet supply apparatus according to claim 1, wherein the set tray includes an engaging member that engages with the sheet holder. A sheet feeding device according to claim 1;
An image forming unit for forming an image on a sheet supplied from the sheet supply device;
An image forming apparatus comprising: a control unit that controls an image forming process of the image forming unit based on a determination result of the determination unit.

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