JP2013028460A - Sheet supply device, image forming apparatus, image forming system, and sheet remaining amount detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively detect a remaining sheet amount even after starting to supply a sheet.SOLUTION: A sheet supply device includes: a tray on which the sheet is stacked; a feed roller that feeds the sheet stacked on the tray; a tray lifting motor 42 in which a driving current flows to generate a driving force; a push-up lever that is driven by the tray lifting motor 42 and brings the sheet stacked on the uppermost portion of the tray into contact with sheet feeding member by pushing up the tray; a motor current detection circuit 43 that detects the driving current flowing into the tray lifting motor 42 and outputs a current value of the detected driving current; a storage part 45 that stores first corresponding data that defines a corresponding relationship of the current value of the driving current flowing into the tray lifting motor 42 with a stacking amount of the sheets stacked on the tray; and a controller 46 that refers to the first corresponding data to detect the remaining amount of the sheets stacked on the tray from the current value that is outputted by the motor current detection circuit 43.

Description

  The present invention relates to a paper feeding device, an image forming apparatus, an image forming system, and a remaining paper amount detection method.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a printing apparatus or a copying machine that feeds a sheet using a multi-stage sheet cassette and forms an image on the fed sheet is known. Some image forming apparatuses detect the remaining amount of paper stored in a paper feed cassette and notify the user of it in order to improve user convenience.

  For example, in Patent Document 1, the remaining amount of paper before the start of paper feeding is determined from the time from when the tray (bottom plate) provided in the paper feeding cassette is pushed up until the paper stacked on the tray comes into contact with the feed roller. A technique for calculating the value is disclosed. There is also a technique for detecting the remaining amount of paper by detecting the rotation angle of the tray with a device such as an encoder or a sensor.

  However, the former technique described above can only detect the remaining amount of paper before the start of paper feeding, and cannot detect the remaining amount of paper after the start of paper feeding. In the latter technique described above, since it is necessary to install a device on the tray, the cost is increased.

  The present invention has been made in view of the above circumstances. A sheet feeding device, an image forming apparatus, an image forming system, and a sheet remaining amount capable of detecting the remaining amount of sheets even after the start of sheet feeding without cost. An object is to provide a quantity detection method.

  In order to solve the above-described problem and achieve the object, a sheet feeding device according to one aspect of the present invention includes a tray for stacking sheets, a sheet feeding member for feeding sheets stacked on the tray, and a drive current. Flows to the drive means, a drive means for generating a drive force by flowing, a push-up member driven by the drive means to push up the tray and bring the uppermost sheet of the tray into contact with the paper feed member A detecting means for detecting a driving current and outputting the detected current value of the driving current, and a correspondence relation between the current value of the driving current flowing through the driving means and the amount of sheets loaded on the tray are defined. Storage means for storing first correspondence data; control means for referring to the first correspondence data; for detecting the remaining amount of paper stacked on the tray from the current value output by the detection means; The Characterized in that it obtain.

  An image forming apparatus according to another aspect of the present invention forms an image on a tray for stacking sheets, a sheet feeding member for feeding sheets stacked on the tray, and a sheet fed from the sheet feeding member. Image forming means for driving, driving means for generating a driving force when a driving current flows, and driving by the driving means to push up the tray and bring the uppermost sheet of the tray into contact with the paper feeding member A member, detection means for detecting a drive current flowing through the drive means, and outputting the detected current value of the drive current, a current value of the drive current flowing through the drive means, and a stack of sheets stacked on the tray Storage means for storing first correspondence data that defines a correspondence relationship with the amount, and sheets stacked on the tray from the current value output by the detection means with reference to the first correspondence data Characterized in that it comprises control means for detecting the remaining amount, the.

  An image forming system according to another aspect of the present invention is an image forming system including a paper feeding device and an image forming device, and the paper feeding device is loaded on a tray on which paper is stacked. A sheet feeding member for feeding out the sheet, a driving unit for generating a driving force when a driving current flows, and a drive unit that is driven by the driving unit to push up the tray so that the uppermost sheet of the tray is fed to the sheet feeding member. A push-up member in contact with the drive means, a detection means for detecting a drive current flowing through the drive means, and outputting a detected current value of the drive current, a current value of the drive current flowing through the drive means and the tray loaded on the tray Storage means for storing first correspondence data that defines a correspondence relationship with the amount of loaded paper, and referring to the first correspondence data, the current value output by the detection means is loaded on the tray. And a control means for detecting the remaining amount of paper that is, the image forming apparatus is characterized by comprising an image forming means for forming an image on a sheet fed from the sheet feeding device.

  A remaining paper amount detection method according to another aspect of the present invention is a remaining paper amount detection method executed by a paper feeding device, wherein the paper feeding device is loaded with paper when a drive current is applied. A drive unit that pushes up the tray being pushed up by the push-up member so that the uppermost sheet loaded on the tray comes into contact with the paper feed member, and a current value of a drive current that flows through the drive unit and the tray loaded on the tray Storage means for storing first correspondence data that defines a correspondence relationship with the amount of loaded paper, and the detection means detects the drive current flowing through the drive means, and the detected current value of the drive current is detected. A detection step of outputting, and a detection step of detecting a remaining amount of paper stacked on the tray from the current value output by the detection step with reference to the first correspondence data. Include And wherein the door.

  According to the present invention, it is possible to detect the remaining amount of paper even after the start of paper feeding without incurring costs.

FIG. 1 is an external view showing an example of a copying machine according to the present embodiment. FIG. 2 is a cross-sectional view showing an example of a paper feed mechanism of the copying machine according to the present embodiment. FIG. 3 is a cross-sectional view showing an example of a paper feed mechanism of the copying machine according to the present embodiment. FIG. 4 is a block diagram showing an example of the electrical configuration of the copying machine according to the present embodiment. FIG. 5 is a diagram illustrating an example of a current waveform detected by the motor current detection circuit of the present embodiment. FIG. 6 is a diagram illustrating an example of a current waveform detected by the motor current detection circuit of the present embodiment. FIG. 7 is a graph showing an example of the relationship between the initial tray rising time and the paper stacking amount and the relationship between the current value and the paper stacking amount in the copying machine of this embodiment. FIG. 8 is a flowchart showing an example of the remaining paper amount detection process executed by the copier of this embodiment. FIG. 9 is a diagram illustrating an example of a correspondence table according to a modification. FIG. 10 is a diagram illustrating an example of a correspondence table according to a modification. FIG. 11 is an external view showing an example of a modified image forming system. FIG. 12 is a block diagram illustrating an example of a hardware configuration of the copier according to the embodiment and the modification.

  Hereinafter, embodiments of a sheet feeding device, an image forming apparatus, an image forming system, and a sheet remaining amount detecting method according to the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, a copying machine will be described as an example of the image forming apparatus, but the present invention is not limited to this. The image forming apparatus may be an apparatus that feeds paper and forms an image on the fed paper. For example, the image forming apparatus may be a printing apparatus or a multifunction peripheral. Note that a multifunction peripheral is a device having at least two functions among a printing function, a copying function, a scanner function, and a facsimile function.

  First, the configuration of the copier of this embodiment will be described.

  FIG. 1 is an external view showing an example of a copying machine 1 according to the present embodiment. As shown in FIG. 1, the copying machine 1 includes a main body 2, a document table cover 3, paper feed cassettes C <b> 1 and C <b> 2, an operation unit 5, a display unit 6, and a paper discharge tray 9. The document table cover 3 is supported on the upper surface 2a of the main body 2 so as to be openable and closable. The sheet cassettes C1 and C2 store sheets. The paper feed cassettes C1 and C2 are detachably attached to the front surface 2b of the main body 2, and are slid in the horizontal direction by the guidance of the main body 2 and attached to the main body 2. The operation unit 5 is for performing setting operations such as start of copying, number of copies, and copy density. The display unit 6 displays the paper size and the remaining amount of paper stored in the paper feed cassettes C1 and C2. The operation unit 5 and the display unit 6 are provided on the front side of the document table cover 3 on the upper surface 2 a of the main body 2. The copied paper (printed material) is discharged to the paper discharge tray 9. The paper discharge tray 9 is provided on the side surface 2 c of the main body 2.

  2 and 3 are cross-sectional views illustrating an example of a paper feed mechanism of the copying machine 1 according to the present embodiment. As shown in FIGS. 2 and 3, the copying machine 1 includes a drive shaft 11, a driven shaft 12, a delivery roller 13, a transport roller 14, a separating roller 15, a tray upper limit detection arm 16, and a tray upper limit sensor. 17, a no-paper sensor 18, a support frame 19, a spring 20, a paper feed cassette C 1, a tray 21, a rotation shaft 22, and a push-up lever 23. 2 shows a state in which the tray 21 provided in the paper feed cassette C1 is positioned at the initial position (home position), and FIG. 3 can feed paper stored in the paper feed cassette C1. The tray 21 is pushed up and the uppermost sheet stacked on the tray 21 is in contact with the feed roller 13. FIG. 4 is a block diagram illustrating an example of an electrical configuration of the copying machine 1 according to the present embodiment. As shown in FIG. 4, the copying machine 1 includes a motor drive circuit 41, a tray raising motor 42, a motor current detection circuit 43, a tray upper limit sensor 17, a no-paper sensor 18, a time measurement unit 44, The storage unit 45, the control unit 46, the display unit 6, and the operation unit 5 are provided.

  Since the paper feed mechanism of the copying machine 1 has a common configuration for both the paper feed cassettes C1 and C2, the paper feed cassette C1 will be described below, and the description of the paper feed cassette C2 will be omitted.

  The drive shaft 11 is rotatably supported by a support frame 19 and the transport roller 14 is coaxially integrated. The driven shaft 12 is rotatably supported by the support frame 19 and the delivery roller 13 is coaxially integrated. A connecting gear (not shown) is installed in the middle of the gear integrated with each of the drive shaft 11 and the driven shaft 12. Accordingly, the feed roller 13 and the transport roller 14 are rotated in the same direction by the drive shaft 11 connected to the power system of the main body 2. The feed roller 13 is positioned away from the paper feed cassette C1. The transport roller 14 is located downstream of the delivery roller 13 in the paper transport direction. The separating roller 15 is positioned in pressure contact with the conveying roller 14. The conveying roller 14 and the separating roller 15 constitute a pair of ironing rollers for conveying the sheet.

  The tray upper limit detection arm 16 is installed on the support frame 19 and is held rotatably with respect to the drive shaft 11. The tray upper limit sensor 17 is positioned close to the lower end of the tray upper limit detection arm 16 (for example, a photo interrupter). The no-paper sensor 18 (for example, a reflection type photo sensor) is installed below the tray upper limit sensor 17. The tray upper limit sensor 17 and the no-sheet sensor 18 are connected to the control unit 46.

  The support frame 19 is rotatably held with respect to the drive shaft 11 and is urged upward by a spring 20. For this reason, the delivery roller 13 and the tray upper limit detection arm 16 rotate counterclockwise around the drive shaft 11 as a rotation center.

  Each of the above members constitutes a paper transport system, and is mainly disposed above the storage space of the paper feed cassette C1.

  The tray 21 is provided in the paper feed cassette C1, and the sheets P are stacked. The rotation shaft 22 is supported by a support fitting (not shown). Further, a spring pin is press-fitted and fixed to the end of the rotating shaft 22, and this spring pin is configured to engage with the output shaft of the tray raising motor 42 to transmit the rotational driving force. The tray raising motor 42 is composed of a combination of a DC motor and a gear train, and is installed behind the rotating shaft 22 (on the non-operator side), and is engaged with a spring pin by a pulley having a groove. The push-up lever 23 (an example of a push-up member) is integrated with the rotating shaft 22 and tilts the tray 21 by pushing up one end of the tray 21 from below and raising it.

  The motor drive circuit 41 is connected to the output port of the control unit 46, and sends a drive current to a tray raising motor 42 which is a drive motor for raising one end of the tray 21 of the paper feed cassette C1 to raise the tray. The motor 42 is rotated. The motor drive circuit 41 receives an instruction from the control unit 46, for example, when the power is turned on or when the paper feed cassette C1 is set in the main body 2, and sends a drive current to the tray raising motor 42. Then, the tray raising motor 42 is driven to rotate.

  When the tray raising motor 42 is driven to rotate, a driving force is generated. Here, the driving force corresponds to the rotational force of the motor, that is, the torque, but is not limited thereto. The push-up lever 23 is moved by this driving force. As a result, as shown in FIG. 3, the push-up lever 23 raises one end of the tray 21 of the paper feed cassette C1 from the initial position, and the sheets P stacked on the tray 21 are inclined. The motor current detection circuit 43 (an example of a detection unit) detects the drive current flowing through the tray raising motor 42 and outputs the detected drive current value to the control unit 46. The motor current detection circuit 43 detects the current value as an analog value, converts it to a digital value, and outputs it to the control unit 46. When the uppermost sheet stacked on the tray 21 comes into contact with the feed roller 13 (an example of a sheet feeding member) and the tray upper limit detection arm 16 shuts off the tray upper limit sensor 17, the tray upper limit sensor 17 indicates that the tray 21 has an upper limit. , And notifies the control unit 46 to that effect. When the tray 21 reaches the upper limit, the control unit 46 instructs the motor drive circuit 41 to stop driving the tray raising motor 42. Upon receiving an instruction from the control unit 46, the motor drive circuit 41 stops supplying drive current to the tray lifting motor 42 and stops the rotational driving of the tray lifting motor 42. As a result, the tray 21 stops rising, and the feed roller 13 can feed the abutting paper. An image is formed on the sheet fed by the delivery roller 13 by an image forming mechanism (an example of an image forming unit, not shown in FIGS. 2 to 4).

  Further, when the feeding of the paper by the feeding roller 13 for copying or the like is started, the loading amount of the paper P loaded on the tray 21 is gradually reduced, and the uppermost paper on the tray 21 is fed to the feeding roller 13. Will not come into contact. For this reason, the motor drive circuit 41 receives an instruction from the control unit 46 at a certain timing so that the uppermost sheet of the tray 21 always comes into contact with the feed roller 13, and resumes the rotation drive of the tray raising motor 42. Then, the tray 21 is raised again. In this case as well, the motor current detection circuit 43 detects the drive current flowing through the tray raising motor 42.

  A motor drive circuit, a tray raising motor, and a motor current detection circuit are prepared for each sheet cassette. In the example shown in FIG. 4, the motor drive circuit 41 for the sheet cassette C1, the tray raising motor. 42 and the motor current detection circuit 43 are illustrated, and a motor drive circuit for the paper feed cassette C2, a tray raising motor, and a motor current detection circuit are not shown.

  The time measuring unit 44 is connected to the control unit 46, and from when the tray 21 starts to rise at the initial position until the uppermost sheet loaded on the tray 21 comes into contact with the feed roller 13 and stops rising. The initial tray rise time (an example of the initial rise time), which is the time of the above, is measured. However, the time measuring unit 44 does not measure the rising time of the tray 21 with respect to the rising of the tray 21 during paper feeding. Details of the method for measuring the initial tray rise time will be described later.

  The storage unit 45 is connected to the control unit 46 and can be realized by, for example, an HDD (Hard Disk Drive), a RAM (Random Access Memory), a ROM (Read Only Memory), or the like. The storage unit 45 stores first correspondence data that defines a correspondence relationship between the current value of the drive current flowing through the tray lifting motor 42 and the amount of sheets stacked on the tray 21. Specifically, the storage unit 45 calculates, as the first correspondence data, a feeding amount for calculating the stacking amount after the sheet feeding on the tray 21 is started from the current value output by the motor current detection circuit 43. Stores the load amount calculation formula after starting paper. In addition, the storage unit 45 stores second correspondence data that defines a correspondence relationship between the initial tray rising time measured by the time measurement unit 44 and the amount of sheets loaded on the tray 21. Specifically, the storage unit 45 calculates, as the second correspondence data, a stacking amount of the sheets stacked on the tray 21 before starting feeding from the initial tray rising time measured by the time measuring unit 44. Stores an initial paper loading amount calculation formula. The details of each data stored in the storage unit 45 will be described later.

  The control unit 46 controls each unit of the copying machine 1 and can be realized by, for example, a CPU (Central Processing Unit). The display unit 6 and the operation unit 5 are also connected to the control unit 46. The control unit 46 refers to the first correspondence data, and detects the remaining amount of paper stacked on the tray 21 from the current value output by the motor current detection circuit 43. Specifically, the control unit 46 applies the current value output by the motor current detection circuit 43 after the paper feeding by the feed roller 13 is started to the stacking amount calculation formula after the paper feeding is started, The amount of paper loaded on the paper 21 is calculated, and the remaining amount after the start of paper feeding is detected. Then, the control unit 46 informs the display unit 6 (an example of a notification unit) of the detected remaining amount of paper.

  Further, the control unit 46 refers to the second correspondence data, and detects the remaining amount of the sheets stacked on the tray 21 before the start of feeding from the initial tray rising time measured by the time measuring unit 44. Specifically, the control unit 46 applies the initial tray rising time measured by the time measuring unit 44 to the initial paper stacking amount calculation formula, calculates the stacking amount of the papers stacked on the tray 21, and Detect the remaining amount before starting feeding. Then, the control unit 46 informs the display unit 6 of the detected remaining amount of paper. Details of the detection method of the remaining amount of paper will be described later.

  Next, the principle of the paper remaining amount detection method by the copying machine of this embodiment will be described.

  5 and 6 are diagrams showing examples of current waveforms detected by the motor current detection circuit 43 of the present embodiment. FIG. 5 shows a current waveform from when the sheet cassette C1 in which one A4 sheet is stacked on the tray 21 is set to the main body 2 until the tray 21 stops rising. FIG. 6 shows a current waveform from when the paper cassette C1 loaded with 500 A4 sheets on the tray 21 is set to the main body 2 until the tray 21 stops rising.

  In the example shown in FIGS. 5 and 6, “A” indicates the time when the paper feed cassette C <b> 1 is set in the main body 2. When the paper feed cassette C1 is set in the main body 2, the motor drive circuit 41 starts the rotational drive of the tray raising motor 42, and an activation current instantaneously flows in the motor drive circuit 41.

  “B” indicates a period from when the paper feed cassette C1 is set to the main body 2 until the push-up lever 23 starts to rotate. Even when the tray raising motor 42 starts to rotate, it takes time for the rotational driving force of the tray raising motor 42 to be transmitted to the push-up lever 23 due to various mechanical backlash and software waiting time. . For this reason, there is a time lag from when the tray raising motor 42 starts to rotate until the push-up lever 23 starts to rotate. When the rotational driving force of the tray raising motor 42 is transmitted to the push-up lever 23, the push-up lever 23 starts to turn about the turning shaft 22, and the tip of the push-up lever 23 is connected to the tray 21. The tray 21 comes into contact with the bottom surface and starts to rise.

  “C” indicates a period from when the tray 21 starts to rise to when it stops rising. When the tray 21 rises and the upper limit of the rise of the tray 21 is detected by the tray upper limit sensor 17, the motor drive circuit 41 stops the rotation drive of the tray raising motor 42, and the rise of the tray 21 is stopped.

In this embodiment, measuring the initial tray rise time T _o is the time of the time measuring unit 44 "C" period. Time measuring unit 44, "B" period and may be by utilizing the difference in current value between the "C" period measures the initial tray rise time T _o. In addition, the time measuring unit 44 uses the fact that the time of the “B” period is constant (2.2 seconds in the examples shown in FIGS. 5 and 6) regardless of the paper stacking amount. measures the time "C" period, the initial tray rise time T _o by subtracting the time "B" period from the measured time may be measured. The motor current detection circuit 43 detects the drive current flowing through the tray raising motor 42 during the “C” period, that is, when the tray 21 is raised, and outputs a current value _Io . In the example shown in FIG. 5, the initial tray rise time _{T o} is 3.0 seconds, the current value _{I o} is a 80 mA, in the example shown in FIG. 6, the initial tray rise time _{T o} is 1 The current value _Io is 240 mA for 4 seconds.

  As described above, in the example shown in FIGS. 5 and 6, the current waveform from when the paper feed cassette C <b> 1 is set to the main body 2 until the tray 21 stops rising has been described. Even in the case of re-raising, except for the initialization time, the current waveform from when the power is turned on until the tray 21 stops rising is the same as the current waveform shown in FIGS.

Figure 7 is a graph showing an example of the relationship between the relationship and the current value I _o and sheet stacking amount of the initial tray rise time T _o and the paper stacking amount in the copying machine 1 of the present embodiment.

Tray elevating motor 42 of the present embodiment, rotating at a constant speed, the initial tray rise time T _o, the sheet load capacity of the tray 21 decreases in proportion to the increase of (height of the sheets stacked) . Therefore, the initial sheet loading value calculation formula for calculating the sheet stacking amount from the initial tray rise time T _o, as shown in FIG. 7, can be described by a linear function. In the example shown in FIG. 7, the sheet stacking amount is 0%, the initial tray rise time _T o (0) in the case of (0 sheets), when the sheet stacking amount is 100% (600 sheets) Initial trays rise time _{T o} From (100), the initial paper loading amount calculation formula is calculated in advance. The initial tray rise time T _{o (0)} and the initial tray rise time T _{o (100)} are also calculated in advance in a manner similar to that described in FIGS. The initial tray rise time T _{o (0)} is independent of the paper, the initial tray rise time T _{o (100)} does not depend on the paper, because determined by the height of the sheets stacked, both This value is unique to the copying machine 1.

In the present embodiment, when the power is turned on or the paper feeding cassette C1 is set in the main body 2, the control unit 46 uses the initial paper loading amount calculation formula before starting the paper feeding of the paper loaded on the tray 21. Detect the remaining amount of paper. For example, in the example shown in FIG. 6, since the initial tray rise time T _o is 1.4 seconds, the control unit 46 substitutes the initial tray rise time T _{o =} 1.4 in the initial sheet loading value calculation formula Thus, the paper stacking amount = 83% (500 sheets) is calculated, and the remaining amount of paper is detected. Then, the control unit 46 displays the detected remaining amount of paper on the display unit 6. When the remaining amount of paper before the start of feeding exceeds 100% (600 sheets), the tray upper limit sensor 17 detects the upper limit before the tray 21 is raised. tray rise time T _o is not measured. In this case, the control unit 46 detects the remaining amount of paper with the paper stacking amount = 100% (600 sheets), and causes the display unit 6 to display the detected remaining amount of paper.

Further, the current value _Io of the tray raising motor 42 according to the present embodiment increases in proportion to an increase in the load of the tray raising motor 42, that is, an increase in the sheet stacking amount of the tray 21. Therefore, a post-feed start stacking amount calculation formula for calculating the post-feed start stacking amount from the current value _Io can also be described by a linear function as shown in FIG. In the example illustrated in FIG. 7, a formula for calculating the stacking amount after the start of feeding is calculated in advance from the current value I _o (0) when the sheet stacking amount is 0% (0 sheets). The current value I _o (0) is also calculated in advance as a value obtained by adding the load of the driving unit to the no-load current of the tray raising motor 42. In addition, the inclination of the formula for calculating the load amount after the start of feeding is equivalent to the reciprocal of the torque constant of the tray lifting motor 42 and is uniquely determined by the tray lifting motor 42, and therefore has a value unique to the copying machine 1.

In the present embodiment, the control unit 46 detects the remaining amount of paper after the start of feeding of the sheets stacked on the tray 21 by using the post-feed start stacking amount calculation formula after starting the sheet feeding. For example, when the current value I _o is 240 mA when the tray 21 is raised again after the start of paper feeding, the control unit 46 substitutes the current value I _o = 240 mA into the stacking amount calculation formula after starting feeding. Thus, the paper stacking amount = 83% (500 sheets) is calculated, and the remaining amount of paper is detected. Then, the control unit 46 displays the detected remaining amount of paper on the display unit 6.

  Next, the operation of the copier of this embodiment will be described.

  FIG. 8 is a flowchart showing an example of the remaining sheet detection process executed by the copying machine 1 of this embodiment.

  When the power is turned on or the paper feed cassette C1 is set in the main body 2 and the paper out sensor 18 detects that there is no paper in the paper feed cassette C1 (Yes in step S100), the control unit 46 determines that the paper is The absence is displayed on the display unit 6 (step S136), and the process is terminated.

  On the other hand, if it is not detected by the paper absence sensor 18 that there is no paper in the paper feed cassette C1 (No in step S100), the paper size (size) is detected by a paper size sensor (not shown) (step S102). The unit 46 confirms whether or not the tray 21 is positioned at the upper limit from the output signal of the tray upper limit sensor 17 (step S104).

  When the tray 21 is located at the upper limit (Yes in step S104), the process proceeds to step S114. On the other hand, when the tray 21 is not positioned at the upper limit (No in step S104), the motor drive circuit 41 receives an instruction from the control unit 46, and sends a drive current to the tray lifting motor 42 to rotate the tray lifting motor 42. Then, the push-up lever 23 starts to raise the tray 21 of the paper feed cassette C1 from the initial position (step S106).

Subsequently, the time measuring unit 44 raises the initial tray until the uppermost sheet loaded on the tray 21 contacts the feed roller 13 and the tray upper limit sensor 17 detects that the tray 21 has reached the upper limit. measuring the time _{T o} (step S108, No at step S110).

  Subsequently, when the tray upper limit sensor 17 detects that the tray 21 has reached the upper limit (Yes in step S110), the control unit 46 instructs the motor drive circuit 41 to stop driving the tray raising motor 42, The motor drive circuit 41 stops the rotational drive of the tray raising motor 42, and the tray 21 stops raising (step S112).

Subsequently, the control unit 46 calculates the load of the sheets stacked on the tray 21 by applying the initial tray rise time T _o measured by the time measuring unit 44 to the initial sheet loading value calculation formula, the paper The remaining amount before the start of feeding is detected (step S114). However, when the tray 21 is positioned at the upper limit in step S104, the control unit 46 detects the remaining amount of paper with the paper stacking amount = 100%. Then, the control unit 46 causes the display unit 6 to display the detected remaining amount of the paper before starting feeding (step S116).

  Subsequently, when the user performs a copying operation using the operation unit 5, the control unit 46 starts feeding the paper that is in contact with the delivery roller 13 and performs a copying operation (step S 118).

  Subsequently, the control unit 46 checks whether or not the tray 21 is located at the upper limit from the output signal of the tray upper limit sensor 17 (step S120). This is performed in order to determine whether the height of the tray 21 is appropriate because the sheet stacking amount decreases due to sheet feeding.

  When the tray 21 is located at the upper limit (Yes in step S120), the process proceeds to step S130. On the other hand, when the tray 21 is not located at the upper limit (No in step S120), the motor drive circuit 41 receives an instruction from the control unit 46, and sends a drive current to the tray lifting motor 42 to rotate the tray lifting motor 42. Then, the push-up lever 23 starts to raise the tray 21 of the paper feed cassette C1 from the initial position (step S122).

Subsequently, until the uppermost sheet loaded on the tray 21 comes into contact with the feed roller 13 and the tray upper limit sensor 17 detects that the tray 21 has reached the upper limit, the motor current detection circuit 43 moves up the tray. The drive current flowing through the motor 42 is detected, and the detected drive current value _Io is output to the control unit 46 (No in step S124 and step S126).

  Subsequently, when the tray upper limit sensor 17 detects that the tray 21 has reached the upper limit (Yes in step S126), the control unit 46 instructs the motor drive circuit 41 to stop driving the tray raising motor 42, The motor drive circuit 41 stops the rotational drive of the tray raising motor 42, and the tray 21 stops raising (step S128).

Subsequently, when the absence of paper sensor 18 detects that there is no paper in the paper feed cassette C1 (Yes in step S130), the control unit 46 displays on the display unit 6 that there is no paper (step S136). The process ends. On the other hand, and that the paper in the paper cassette C1 is not is not detected by the no-paper sensor 18 (No at step S130), the control unit 46, the sheet feeding start after the output current value I _o by the motor current detecting circuit 43 Applying to the load amount calculation formula, the load amount of the paper loaded on the tray 21 is calculated, and the remaining amount after the start of paper feed is detected (step S132). Then, the control unit 46 causes the display unit 6 to display the detected remaining amount of paper after the start of feeding (step S134), and returns to step S118.

  When the paper feed cassette C1 is pulled out from the main body 2 during the paper remaining amount detection process shown in FIG. It is done from the beginning.

  As described above, in the present embodiment, since the remaining amount of paper is detected from the current value of the drive current flowing through the tray raising motor 42, an encoder and a sensor are not provided to detect the remaining amount of paper, and after the start of feeding. In this case, the remaining amount of paper can be detected. That is, according to the present embodiment, it is possible to detect the remaining amount of paper even after the start of feeding without cost. In addition, according to the present embodiment, it is possible to notify the user that paper will soon be exhausted by notifying the remaining amount of paper every time paper is passed.

  In this embodiment, the remaining amount of paper is detected from the initial tray rising time before the start of paper feeding, and the remaining amount of paper is detected from the current value of the drive current after the start of paper feeding. Can be accurately detected.

(Modification)
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible.

(Modification 1)
In the embodiment described above, the storage amount calculation formula and the initial paper stacking amount calculation formula after starting feeding are stored in the storage unit 45, but a correspondence table that defines the correspondence among the initial tray rising time, current value, and paper stacking amount ( An example of the first correspondence data and the second correspondence data) may be stored.

FIG. 9 is a diagram illustrating an example of a correspondence table according to a modification. As shown in FIG. 9, the correspondence table, and associates the initial tray rise time T _o and sheet loading amount and the current value I _o and symbols. The correspondence relationship between the initial tray rise time T _o and the sheet stacking amount, can be identified in a manner similar calculation method of the initial sheet loading value calculation formula, correspondence between the sheet stacking amount and a current value I _o is fed It can be specified by a method similar to the calculation method of the load amount calculation formula after starting paper (see FIG. 7).

When using the correspondence table shown in FIG. 9, the control unit 46 refers to the correspondence table to identify the payload of the paper associated with the measured initial trays rise time T _o by the time measuring unit 44, the paper Detects the remaining amount of paper before starting feeding. Further, the control unit 46 refers to the correspondence table and causes the display unit 6 to display a symbol associated with the specified sheet stacking amount. The control unit 46 refers to the correspondence table, the loading amount of paper associated with the output current value I _o by the motor current detecting circuit 43 after the sheet feeding is started of paper by the delivery roller 13 Is detected, and the remaining amount of paper after feeding is detected. Further, the control unit 46 refers to the correspondence table and causes the display unit 6 to display a symbol associated with the specified sheet stacking amount.

  The correspondence table is not limited to the three-stage division as shown in FIG. 9, and may be divided into any stages such as the four stages as shown in FIG. Further, the symbol may be an icon as shown in FIGS. 9 and 10, a bar graph, or the like, and any symbol can be used as long as it can inform the user of the remaining amount of paper.

(Modification 2)
In the above embodiment, the remaining amount of paper is detected only from the initial tray rising time before the start of paper feeding. However, the remaining amount of paper is detected using both the initial tray rising time and the current value of the drive current. It may be. As a result, the reliability of the detected remaining amount of paper can be improved. Further, the remaining amount of paper may be detected from only the current value of the drive current even before the start of paper feeding.

(Modification 3)
In the above embodiment, if the initial tray rise time or the current value of the drive current is outside the predicted value range, the machine may be abnormal. Also good. Thereby, the malfunction of a machine can also be detected.

(Modification 4)
In the above embodiment, the detected remaining amount of paper is displayed as it is, but a symbol corresponding to the remaining amount of paper (paper stacking amount) may be displayed. In this case, the storage unit 45 may store a symbol table in which the paper stacking amount is associated with the symbol, and display the symbol corresponding to the paper stacking amount calculated by the control unit 46 on the display unit 6.

(Modification 5)
In the above embodiment, the paper feeding cassette has been described as an example. However, the paper feeding cassette is of a type that feeds paper by raising the tray and bringing the uppermost paper loaded on the tray into contact with the feed roller. For example, the present invention can be applied to a large-capacity paper feed tray (LCT).

(Modification 6)
In the above embodiment, the copying machine 1 including the paper feeding mechanism and the image forming mechanism has been described as an example. However, separate apparatuses may be provided with the paper feeding mechanism and the image forming mechanism. For example, as illustrated in FIG. 11, in the case of an image forming system 101 including a sheet feeding device 102 and an image forming apparatus 103, the sheet feeding device 102 includes a sheet feeding mechanism, and the image forming apparatus 103 includes an image forming mechanism. You can do it.

(Hardware configuration)
An example of the hardware configuration of the copying machine 1 according to the embodiment and the modification will be described.

  FIG. 12 is a block diagram illustrating an example of a hardware configuration of the copying machine 1 according to the embodiment and the modification. As shown in FIG. 12, the copying machine 1 of the above embodiment and the modification has a configuration in which a controller 910 and an engine unit (Engine) 960 (an example of an image forming unit) are connected by a PCI (Peripheral Component Interconnect) bus. . The controller 910 is a controller that controls the entire copying machine, drawing, communication, and input from the operation display unit 920. The engine unit 960 is a printer engine that can be connected to a PCI bus, and is, for example, a monochrome plotter, a 1-drum color plotter, a 4-drum color plotter, a scanner, or a fax unit. The engine unit 960 includes an image processing part such as error diffusion and gamma conversion in addition to a so-called engine part such as a plotter.

  The controller 910 includes a CPU 911, a north bridge (NB) 913, a system memory (MEM-P) 912, a south bridge (SB) 914, a local memory (MEM-C) 917, and an ASIC (Application Specific Integrated Circuit). 916 and a hard disk drive (HDD) 918, and the North Bridge (NB) 913 and the ASIC 916 are connected by an AGP (Accelerated Graphics Port) bus 915. The MEM-P 912 further includes a ROM 912a and a RAM 912b.

  The CPU 911 performs overall control of the copying machine, has a chip set including the NB 913, the MEM-P 912, and the SB 914, and is connected to other devices via the chip set.

  The NB 913 is a bridge for connecting the CPU 911 to the MEM-P 912, SB 914, and the AGP bus 915, and includes a memory controller that controls reading and writing to the MEM-P 912, a PCI master, and an AGP target.

  The MEM-P 912 is a system memory used as a memory for storing programs and data, a memory for developing programs and data, a memory for drawing printers, and the like, and includes a ROM 912a and a RAM 912b. The ROM 912a is a read-only memory used as a memory for storing programs and data, and the RAM 912b is a writable and readable memory used as a program / data development memory, a printer drawing memory, and the like.

  The SB 914 is a bridge for connecting the NB 913 to a PCI device and a peripheral device. The SB 914 is connected to the NB 913 via a PCI bus, and a network interface (I / F) unit and the like are also connected to the PCI bus.

  The ASIC 916 is an IC (Integrated Circuit) for image processing having hardware elements for image processing, and has a role of a bridge for connecting the AGP bus 915, the PCI bus, the HDD 918, and the MEM-C 917, respectively. The ASIC 916 includes a PCI target and an AGP master, an arbiter (ARB) that forms the core of the ASIC 916, a memory controller that controls the MEM-C 917, and a plurality of DMACs (Direct Memory) that perform image data rotation by hardware logic and the like. Access Controller) and a PCI unit that performs data transfer between the engine unit 960 via the PCI bus. Connected to the ASIC 916 are a USB (Universal Serial Bus) 940 and an IEEE 1394 (the Institute of Electrical and Electronics Engineers 1394) interface 950. The operation display unit 920 is directly connected to the ASIC 916.

  The MEM-C 917 is a local memory used as a copy image buffer and a code buffer, and the HDD 918 is a storage for storing image data, programs, font data, and forms.

  The AGP bus 915 is a bus interface for a graphics accelerator card proposed for speeding up graphics processing. The AGP bus 915 speeds up the graphics accelerator card by directly accessing the MEM-P 912 with high throughput. It is.

DESCRIPTION OF SYMBOLS 1 Copier 2 Main body 3 Document cover C1, C2 Paper feed cassette 5 Operation part 6 Display part 9 Paper discharge tray 11 Drive shaft 12 Driven shaft 13 Feeding roller 14 Carrying roller 15 Separation roller 16 Tray upper limit detection arm 17 Tray upper limit sensor 18 No-sheet sensor 19 Support frame 20 Spring 21 Tray 22 Rotating shaft 23 Push-up lever 41 Motor drive circuit 42 Tray raising motor 43 Motor current detection circuit 44 Time measurement unit 45 Storage unit 46 Control unit 101 Image forming system 102 Paper feeding device 103 Image forming apparatus 910 Controller 911 CPU
912 System memory 912a ROM
912b RAM
913 North Bridge 914 South Bridge 915 AGP Bus 916 ASIC
917 Local memory 918 Hard disk drive 920 Operation display unit 940 USB
950 IEEE1394 interface 960 engine part

JP 2001-48380 A

Claims (7)

A tray for loading paper,
A paper feeding member for sending out the paper loaded on the tray;
Driving means for generating a driving force when a driving current flows;
A push-up member driven by the drive means to push up the tray and bring the uppermost sheet of the tray into contact with the paper feed member;
Detecting means for detecting a driving current flowing in the driving means and outputting a current value of the detected driving current;
Storage means for storing first correspondence data defining a correspondence relationship between a current value of a driving current flowing through the driving means and a stacking amount of sheets stacked on the tray;
Control means for referring to the first correspondence data and detecting a remaining amount of paper stacked on the tray from the current value output by the detection means;
A sheet feeding device comprising:   The control means refers to the first correspondence data, and loads the paper on the tray from the current value output by the detection means after the paper feeding member starts feeding paper that is in contact with the paper. The paper feeding device according to claim 1, wherein a remaining amount of the paper that has been used after the start of paper feeding is detected. A measuring means for measuring an initial rising time from when the tray starts to rise at an initial position until the uppermost sheet stacked on the tray comes into contact with the paper feeding member and stops rising;
The storage means further stores second correspondence data defining a correspondence relationship between the initial rising time and the amount of paper loaded on the tray;
The control means refers to the second correspondence data, and detects the remaining amount of the paper stacked on the tray before starting feeding from the initial rising time measured by the measuring means. The sheet feeding device according to claim 2.   The sheet feeding device according to claim 1, wherein the control unit causes the notification unit to notify the detected remaining amount of the sheet. A tray for loading paper,
A paper feeding member for sending out the paper loaded on the tray;
Image forming means for forming an image on a sheet fed from the sheet feeding member;
Driving means for generating a driving force when a driving current flows;
A push-up member driven by the drive means to push up the tray and bring the uppermost sheet of the tray into contact with the paper feed member;
Detecting means for detecting a driving current flowing in the driving means and outputting a current value of the detected driving current;
Storage means for storing first correspondence data defining a correspondence relationship between a current value of a driving current flowing through the driving means and a stacking amount of sheets stacked on the tray;
Control means for referring to the first correspondence data and detecting a remaining amount of paper stacked on the tray from the current value output by the detection means;
An image forming apparatus comprising: An image forming system comprising a paper feeding device and an image forming device,
The paper feeder is
A tray for loading paper,
A paper feeding member for sending out the paper loaded on the tray;
Driving means for generating a driving force when a driving current flows;
A push-up member driven by the drive means to push up the tray and bring the uppermost sheet of the tray into contact with the paper feed member;
Detecting means for detecting a driving current flowing in the driving means and outputting a current value of the detected driving current;
Storage means for storing first correspondence data defining a correspondence relationship between a current value of a driving current flowing through the driving means and a stacking amount of sheets stacked on the tray;
Control means for detecting the remaining amount of paper stacked on the tray from the current value output by the detection means with reference to the first correspondence data;
The image forming apparatus includes:
An image forming system comprising image forming means for forming an image on a sheet fed from the sheet feeding device. A method for detecting a remaining amount of paper executed by a paper feeder,
The paper feeder is
Driving means for causing the tray on which the paper is stacked to be pushed up by the push-up member and causing the uppermost paper stacked on the tray to come into contact with the paper feeding member by the drive current flowing;
Storage means for storing first correspondence data defining a correspondence relationship between a current value of a drive current flowing through the drive means and a stacking amount of sheets stacked on the tray;
A detecting step for detecting a driving current flowing through the driving unit and outputting a current value of the detected driving current;
A detecting step of detecting a remaining amount of paper stacked on the tray from the current value output by the detecting step with reference to the first correspondence data;
A method for detecting the remaining amount of paper.

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