JP2007238312A - Paper feeding device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding device which reduces a user waiting time due to movement of a placement base, namely enhances easiness of use by the user, and is advantageous in an aspect of cost. <P>SOLUTION: The paper feeding device or the like is provided with: a placement base for placing a sheet member becoming an object to be transferred; a lifting drive motor for lifting the placement base; an upper end detection switch for detecting that an upper end of the sheet member placed on the placement base is arranged at a feeding position for feeding the sheet member to a continuously contacted equipment; a passing detection switch for detecting that the upper end of the sheet member placed on the placement base is passed in a lifting direction; and a lifting speed control means for increasing a lifting speed of the placement base by a lifting drive motor based on passing of the time from starting of lifting of the placement base and for reducing the lifting speed based on the detection by the passing detection switch. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet feeding device and an image forming apparatus, and more particularly to a sheet feeding device and an image forming apparatus that store a large amount of sheet members.

  In an image forming apparatus typified by a copier, a fax machine, a printer, and a multifunction machine equipped with these, a user who uses a large amount of printing paper at a time uses, for example, an optional paper feeding device. The paper feeding device can store thousands of sheets of printing paper, and its height ranges from several tens of centimeters to 1 meter.

  The paper feeding device includes a lifting mechanism on a mounting table on which printing paper is placed, and raises and lowers the lifting mechanism according to the remaining number of printing paper. As a result, the position of the upper end portion of the printing paper is maintained in the vicinity of the position of the paper feed port when transported to the image forming apparatus.

  Japanese Patent Application Laid-Open No. 11-79421 discloses a technique for detecting the amount of printing paper placed on the placement table by a sensor and variably controlling the rising speed of the placement table at a speed according to the detection result. ing.

By the variable control of the rising speed, the time required for the mounting table to move to the upper part of the sheet feeding device when there is little printing paper on the mounting table is shortened, and the usability for the user is improved.
JP-A-11-79421

By the way, in the technology for variably controlling the ascending speed, a large number of sensors are required to detect the amount of printing paper placed on the placing table. There is concern about the rise.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet feeding device and an image forming apparatus that can change the moving speed of the mounting table at a lower cost.

  The present invention employs the following means in order to achieve the above object. In other words, the sheet feeding device according to the present invention includes a mounting table on which a sheet member to be transferred is mounted, a lifting drive motor that lifts and lowers the mounting table, and an upper end portion of the sheet member mounted on the mounting table. An upper end detection switch that detects that the sheet is placed at a supply position for supplying to a connected device, and that the upper end of the sheet member mounted on the mounting table has passed in the upward direction below the upper end detection switch. Ascending speed control that increases the ascending speed of the mounting table by the passage detection switch to be detected and the lifting drive motor based on the passage of time from the start of ascent of the mounting table and decreases the ascending speed based on the detection by the passing detection switch Means.

  In addition, there is a configuration that includes a counting unit that counts the time from when the mounting table starts to rise, and the rising speed control unit increases the rising speed of the mounting table based on the time counted by the counting unit.

  Note that the image forming apparatus can also be provided with a sheet feeding device.

By counting the time from the start of ascent and appropriately increasing the ascent speed based on the count, it is possible to reduce the waiting time of the user accompanying the movement of the mounting table, that is, to improve the user's usability.
Further, since a large number of sensors for detecting the upper end of the printing paper are not required, this is advantageous in terms of cost.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

  The image forming apparatus according to the present invention corresponds to, for example, a scanner, a copier, a fax machine, or a multifunction machine including these. As an example, the operations of the image forming apparatus and the paper feeding apparatus when using a copier will be described.

When a user prints, for example, a document using a copier, the document is placed on the document table 103 or the document table 105 shown in FIG. 1, and a print instruction is given to the operation panel provided near the document table. I do. When the instruction is given, printing is performed by operating the following units.
That is, as illustrated in FIG. 1, the image forming apparatus 100 includes a main body 101 and a paper feeding device 150 attached to a side surface of the main body 101. A document table 103 is provided on the upper surface of the main body 101, and the document table 103 is opened and closed by a platen cover 102. The platen cover 102 is provided with an automatic document feeder 104, a document placement table 105, and a sheet discharge table 109.

  The automatic document feeder 104 includes a document conveyance path 108 formed inside the platen cover 102, a pickup roller 106 and a conveyance roller 107 provided inside the platen cover 102, and the like. The document conveyance path 108 is a document conveyance path that leads from the document placement table 105 to the sheet discharge table 109 via a reading position P where reading is performed by the reading unit 110 provided in the main body 101.

  The automatic document feeder 104 draws each document placed on the document placing table 105 to the inside of the conveyance path 108 by the pickup roller 107, and passes the document drawn by the conveyance roller 106 and the like through the reading position P. The paper is discharged onto the paper discharge tray 109. When the document passes the reading position P, the document is read by the reading unit 110.

  The reading unit 110 is provided below the document table 103. The reading unit 110 includes a light source 111 that illuminates the document table 103 in the main scanning direction, mirrors 112, 113, and 114 that guide light from the document table, and an image sensor 115 that images light guided by the mirror. Has been.

  When the automatic document feeder 104 conveys a document, the light source 111 moves to a position where the reading position P can be irradiated and emits light. Light from the light source 111 is reflected by a document that passes through the document table 103 and passes through the reading position P, and is guided to the image sensor 115 by mirrors 112, 113, and 114. The image sensor 115 captures received light to generate image data of the original.

  The reading unit 110 can read not only the document conveyed by the automatic document feeder 104 but also the document placed on the document table 103. When reading a document placed on the document table 103, the reading unit 110 moves the light source 111 in the sub-scanning direction while emitting light, and irradiates the entire document table 103. In order to guide the reflected light from the document table 103 to the image sensor 115, the mirror 112 moves together with the light source 111, and in order to make the optical path length from the light source 111 to the image sensor 115 constant, the mirrors 113 and 114 The mirror 112 moves at half the speed.

  The image sensor 115 reads the image data of the document placed on the document table 103 based on the light guided to the mirrors 112, 113, 114 in the same way as the document conveyed to the automatic document feeder 104. Generate.

  A printing unit 120 that prints image data is provided below the reading unit 110 of the main body 101. Image data that can be printed by the printing unit 120 is generated by the image sensor 115 as described above, or transmitted from a terminal such as a personal computer connected to the image forming apparatus 100 and a network such as a LAN.

  As a printing method performed by the printing unit 120, an electrophotographic method is used. That is, the photosensitive drum 121 is uniformly charged by the charger 122, and then the photosensitive drum 121 is irradiated by the laser 123 to form a latent image on the photosensitive drum 121, and toner is attached to the latent image by the developing device 124. Printing is performed by forming a visual image and transferring the visible image onto a printing sheet as a sheet member by the transfer roller 125.

  As the printing paper on which the visible image is printed, the paper loaded on the paper feed tray such as the paper feed cassettes 132, 133, 134 or the paper fed from the paper feeder 150 is used.

  When printing, for example, the printing unit 120 pulls out one sheet of printing paper from any one paper feeding tray or the paper feeding device 150 selected by the user using a pickup roller. When using the paper feeding device 150, a paper feeding command from the main body 101 is transmitted to the control unit 157 via the interface 151 provided in the main body 101 and the paper feeding device 150. The control unit 157 that has received the paper feed command transmits a command for supplying the stacked printing paper to the main body 101 from the supply port 206 to each drive circuit, details of which will be described later.

  The supplied printing paper is sent to the registration roller 138 by the conveyance roller 137, and the inclination is corrected by the registration roller 138 and sent between the photosensitive drum 121 and the transfer roller 125.

  When the visible image is transferred to the printing paper fed between the photosensitive drum 121 and the transfer roller 125, the printing unit 120 sends the paper to the fixing device 127 by the conveying belt 126 in order to fix the visible image. The fixing device 127 includes a heating roller 128 with a built-in heater and a pressure roller 129 pressed against the heating roller 128 with a predetermined pressure. When the sheet passes between the heating roller 128 and the pressure roller 129, the visible image is fixed to the sheet by heat and the pressing force to the sheet. The printing unit 120 discharges the sheet that has passed through the fixing device 127 to the discharge tray 130.

  The above is the copy service process using the paper feeding device 150 in the image forming apparatus 100.

  Next, details of the sheet feeding device 150 will be described with reference to the drawings.

  The sheet feeding device 150 is a device that is detachably provided on, for example, a side surface of the image forming apparatus 100, and can exchange commands and the like with the image forming apparatus 100 via the interface 151. Further, the paper feeding device 150 can store a large number of thousands of printing paper 153 inside the housing, and the printing paper is placed on a mountable table 152 provided inside the housing. Loaded. The mounting table 152 is moved up and down by driving a lift drive motor (lift motor) 155 constituting the lift drive mechanism 154.

  Further, as shown in FIG. 2, a sheet detection switch 209 that detects the presence or absence of printing paper and a lower end detection switch 210 that detects the lowest position of the mounting table 152 are provided below the mounting table 152.

  An upper door 156 is provided at the upper part of the paper feeding device 150. When feeding paper, the upper door 156 has the rotation shaft 200 as the central axis and the opposite end to the image forming device 100 is located above the image forming device 100. Opening is possible. An opening detection switch 213 for detecting the opening of the upper door 156 is provided on the upper surface of the opening of the sheet feeding device casing that is exposed only when the upper door 156 is opened, and detects the open / closed state of the upper door 156. Is possible. In addition, a forcible lowering switch 212 that allows the user to forcibly lower the mounting table 152 is provided on the upper surface of the opening. Further, on the upper surface of the opening portion, when the upper door 156 is opened, an elevating drive of an input circuit for connecting a motor driver 154 (elevating drive mechanism) that controls the supply of power to the elevating drive motor 155 and the elevating drive motor 155 is provided. A rising prevention switch means 214 is provided for grounding one end of the motor 155 side.

  In order to operate the elevating drive mechanism 154 so that the upper end of the printing paper 153 on the mounting table 152 is positioned at a height that can be appropriately fed by the paper feed mechanism 201 on the inside of the housing of the upper door 156, An upper end detection switch 211 that detects the position of the upper end portion of the printing paper 153 is provided. The upper end detection switch 211 is configured to open and close together with the upper door 156. The upper end detection switch 211 urges a bar-shaped detection piece having a spherical tip at the bottom by an elastic means such as a spring and presses it against the upper surface of the print paper 153 on the mounting table 152, thereby Detect position.

  In addition, the paper feed mechanism 201 disposed at the upper part of the paper feed device 150 includes an air separation unit 203 that floats one of the upper end portions of the printing paper placed on the placement table 152 and separates them one by one. A sheet pressing member 204 that prevents the printing sheet from being lifted by air blowing in the air separation unit 203; an air conveyance unit 205 that adsorbs and conveys one printing sheet separated by the air separation unit 203 by air suction; , A pair of transport rollers 207 and 208 for sending the print paper transported by the air transport unit 205 to the paper feed port 206 is provided.

  FIG. 3 is a schematic block diagram illustrating a control-related configuration in the sheet feeding device 150. A main body side control unit 302 that controls the image forming apparatus 100 and a paper feeding device side control unit 157 that controls the paper feeding device 150 (hereinafter referred to as a control unit 157) exchange information via an interface 151. A paper detection switch 209, a lower end detection switch 210, an upper end detection switch 211, an opening detection switch 213, a forced lowering switch 212, and a passage detection switch 220 are connected to the control unit 157, and the state of each switch is connected to the control unit 157. Entered. The control means 157 controls the supply of electric power from the power supply 301 to the lifting drive motor 155 by controlling the motor driver 154 constituting the lifting drive mechanism based on the input. By the control of the power supply, the lifting drive motor 155 rotates forward and backward to raise and lower the mounting table 152.

  Next, an operation at the time of replenishing printing paper in the paper feeding device 150 will be described. FIG. 1 shows a state where the printing paper is sufficiently placed. In this state, when the user prints on the image forming apparatus 100, as described above, a paper feed process is performed on the image forming apparatus 100 from the upper end portion of the print paper 153 via the paper feed port 206. The printing paper 153 in the paper feeder 150 is reduced.

  The decrease in the printing paper 154 based on the paper feed is detected when the upper end detection switch 211 is turned off, for example, and a message to that effect is transmitted to the control means 157. The control means 157 that has detected the decrease transmits an ascending signal to the motor driver 154 so as to rotate the ascending / descending drive motor 155 in the forward direction (ascending direction).

  The motor driver 154 that has received the rising signal gives a positive potential to, for example, the input connection 304 of the two input connections 303 and 304 connected to the lifting drive motor 155, and sets the input connection 303 to the ground (earth) state. .

By the operation of the motor driver 154, the elevation drive motor 155 rotates in the forward direction and the mounting table 152 moves upward, so that the upper end of the printing paper 153 turns on the upper end detection switch 211 again.
When the state of the upper end detection switch 211 is input to the control unit 157, the control unit 157 stops the ascending signal to the motor driver 154, thereby stopping the lifting of the lifting platform 152.

  By repeating the above processing, the mounting table 152 rises in response to the decrease in the printing paper 153, and the upper end portion of the printing paper 153 is positioned in the vicinity of the paper feed mechanism 201.

  When all of the printing paper 153 placed on the placement table 152 is discharged from the paper feed slot 206, the paper detection switch 209 detects that fact and transmits it to the control means 157.

Upon receiving the notification that there is no printing paper, the control unit 157 transmits a lowering signal to the motor driver 157 to rotate the lifting drive motor 155 in the reverse direction (downward direction) in order to lower the mounting table 152. . The motor driver 154 that has received the lowering signal places the input connection 304 in the ground state and applies a positive potential to the input connection 303, thereby rotating the lifting drive motor 155 in the reverse direction, that is, lowering the mounting table 152. When the lowering signal is transmitted, the mounting table 152 is lowered and reaches the lowermost end of the paper feeding device 150. When the mounting table 152 reaches the lowermost end in the supply device 150, the lower end detection switch 210 transmits a message to that effect to the control unit 157, and the control unit 157 stops the lifting drive motor 155 to stop the mounting table 152.
When the lowering is completed, the control unit 157 notifies the main body side control unit 302 that there is no printing paper. In the main body side control means 302, for example, in order to notify the user that the printing paper is to be replenished, a paper feed instruction is displayed on the display, or a paper feed is instructed by voice.

  When the user feeds paper to the paper feeder 150, the user first lifts the upper door 156 upward.

  When the opening state is reached, the opening detection switch 213 is turned off, for example, and a message to that effect is transmitted to the control means 157.

  In the above state, for example, when the user places printing paper on the mounting table 152 and closes the upper door 156, the opening detection switch 213 is turned on (closed state), and that fact is transmitted to the control means 157. .

  Receiving the above, the control means 157 transmits an ascending signal to the motor driver 154 in order to raise the mounting table 152 to a position where the upper end detection switch 211 detects the upper end of the printing paper.

  Here, the amount of printing paper replenished (mounted) on the mounting table 152 is based on the user's work. For example, as shown in FIG. 1, the replenishing is performed until the inside of the supply device 150 is full. In some cases, it is rarely supplied as shown in FIG.

When almost no supply is made, the mounting table 152 needs to move from the lowermost position to the uppermost position.
Here, as a characteristic of the elevating drive motor 155, if a large amount of printing paper is replenished, the torque required for the ascent is increased, and the ascent speed cannot be increased. On the other hand, if the amount of printing paper is small, the torque required for rising is small, so that the rising speed can be increased.

  Normally, the lifting drive motor 155 is set at a low speed assuming a maximum torque so that it can be lifted even when a large amount of printing paper is supplied. That is, the ascending speed is set to be slow.

  Therefore, when the mounting table 152 moves at a low speed from the lowermost part to the almost uppermost position, it takes a very long time, and printing is not possible until it moves to the uppermost position. Therefore, a long waiting time occurs for the user.

  In order to prevent such a problem, the sheet feeding device 150 is provided with a passage detection switch 220 that detects that the mounting table 152 has passed in the upward direction below the upper end detection switch 211. In addition, a speed control unit 221 that controls the ascending speed of the mounting table 152 and a counting unit 222 that counts the time since the ascent start are provided based on the elapsed time from the ascent start. Further, the speed control means 221 includes a table shown in Table 1 in the storage means. In the table, the elapsed time (seconds) from the start of ascent and the motor speed at the time elapse (rising speed: mm / sec). ) Are stored in association with each other.

  When the control unit 157 transmits an increase signal to the motor driver 154, the speed control unit 221 constituting the control unit 157 transmits a signal to the count unit 222 to reset the count and start counting. . Further, the motor speed (rising speed) corresponding to the count value by the counting means 222 is acquired from the storage means. Since the count is 0 at the start of ascending, 10 mm / sec is acquired as the motor speed. Subsequently, the speed control unit 221 transmits a speed setting signal indicating that the motor speed is 10 mm / sec to the motor driver 154 based on the acquired value.

  As described above, the ascending speed of the mounting table 152 by the ascending / descending drive motor 155 is set to 10 mm / sec and increases at a speed of 10 mm / sec.

  The speed control unit 221 refers to the count value by the count unit 222 as needed, acquires the motor speed corresponding to the count value, and transmits a speed setting signal to the motor driver 154. This process increases the speed of the mounting table 152 based on the elapsed time from the start of ascent. Based on Table 1 above, for example, the motor speed is increased to 60 mm / sec after an elapsed time of 7 seconds.

  In this state, when the upper end portion of the printing paper 153 on the mounting table 152 passes through the passage detection switch 220, the passage detection switch 220 detects that fact and transmits it to the control means 157.

  When the signal from the passage detection switch 220 is received, the speed control means 221 transmits a signal to the motor driver 154 to set the ascent speed of the elevating drive motor 155 to the minimum speed (here, 10 mm / sec). .

  As a result, the rising speed of the mounting table 152 is reduced, and the rising stops when the upper end portion of the printing paper 153 turns on the upper end detection switch 211.

  As described above, the printing paper 153 is ready to be supplied from the supply port 206, and a message to that effect is transmitted to the main body control unit 302, thereby enabling a copy service using the paper supply device 150.

  As described above, by counting the time from the start of ascent and appropriately increasing the ascent speed based on the count, the waiting time of the user accompanying the movement of the mounting table is reduced, that is, the user's ease of use is improved. Can be made. Further, since a large number of sensors for detecting the upper end of the printing paper are not required, this is advantageous in terms of cost.

  In addition, when the raising / lowering drive motor can be stopped suddenly at the maximum ascending speed of the mounting table 152 (here, 60 mm / sec), the upper end detection switch 211 may also serve as the passage detection switch 220. In this case, when the passage detection switch 220 (upper end detection switch 211) detects the upper end portion of the printing paper, the speed control unit 221 transmits a signal to the motor driver 154 to stop the lifting drive motor 155. To do.

  The passage detection switch 220 only needs to detect the upward movement of the upper surface of the printing paper. For example, an optical sensor that detects the presence of the upper surface by outputting light and receiving the reflected light can be used. In this case, the movement in the upward direction is detected by the change of the light reception from on to off.

  The sheet feeding device and the image forming apparatus according to the present invention reduce the waiting time of the user accompanying the movement of the mounting table, that is, improve the user's ease of use and are advantageous in cost as the sheet feeding device and the image forming apparatus. Useful.

FIG. 3 is a side view illustrating a schematic configuration of an image forming apparatus and a sheet feeding device. The side view which shows the detailed structure of a paper feeder. The schematic block diagram which shows the structure relevant to control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 150 Paper feeding device 152 Mounting base 154 Motor driver 155 Lifting drive motor 157 Paper feeding device side control means 209 Paper detection switch 210 Lower edge detection switch 211 Upper edge detection switch 212 Forced lowering switch 213 Opening detection switch 214 Elevation prevention switch 220 Pass detection switch 221 Speed control means 222 Count means 301 Power supply 302 Main body side control means 303, 304 Input connection

Claims (4)

A mounting table for mounting a sheet member to be transferred;
An elevating drive motor for elevating the mounting table, and
An upper end detection switch for detecting that the upper end portion of the sheet member placed on the mounting table is disposed at a supply position for supplying the sheet member to a connected device;
Below the upper end detection switch, a passage detection switch that detects that the upper end portion of the sheet member placed on the mounting table has passed in the upward direction,
Ascending speed control means for increasing the ascending speed of the mounting table by the ascending / descending drive motor based on the passage of time from the start of ascent of the mounting table and decreasing the ascending speed based on detection by the passage detection switch;
A paper feeder equipped with. It has a counting means that counts the time from the start of rising of the mounting table,
2. The sheet feeding device according to claim 1, wherein the rising speed control means increases the rising speed of the mounting table based on the time counted by the counting means.   The sheet feeding device according to claim 1, wherein the upper end detection switch also serves as the passage detection switch. An image forming apparatus comprising the paper feeding device according to claim 1.

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