JPH0516078A - Sheet binding device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a sheet binding device capable of detecting the presence or absence of staples used for stapling at a small size and at low cost. [Structure] The cam sensor 13 detects the time when the stapler clinches. The current I _M flowing through the motor 11 that drives the stapler is converted into a voltage signal IMOUT by the current detection resistor 2 and the amplifier 3. The CPU 5 compares the voltage signal IMOUT at the time when the stapler is clinched with a preset threshold value to detect the presence or absence of the staple used in the stapler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet binding device for performing a stapling operation by utilizing the rotational force of a motor, and more particularly to a sheet binding device capable of detecting the presence or absence of staples.

[0002]

2. Description of the Related Art Conventionally, for detecting the presence or absence of staples in a sheet binding device, a transmissive or reflective optical sensor is provided in the vicinity of the stapler mounted stapler, and the presence or absence of staples is detected based on the detection result of the optical sensor. Had detected.

[0003]

However, the above-described conventional sheet binding device requires a transmissive or reflective optical sensor for detecting the presence or absence of a needle, and therefore has a problem in downsizing. However, there was a drawback that the cost was also high.

[0004]

In order to solve the above problems, the present invention provides a stapling means for stapling a sheet with a staple, a motor for driving the stapling means, and a current supply to the motor. A power source, a detection unit that detects the current flowing through the motor, and a determination unit that determines the presence or absence of the staple according to the detection result of the detection unit are provided.

[0005]

With the above construction, the judging means judges the presence / absence of the staple according to the detection result of the current flowing through the motor.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit configuration diagram of a sheet binding device according to a first embodiment of the present invention.

Reference numeral 1 denotes a stapling unit for performing a binding operation. A cam sensor 13 for detecting the positions of a motor 11 and a cam 12 for stapling a stapler 21 with a cam 12 is provided.
Etc.

The cam sensor 13 is a transmissive sensor,
A disk 17c having a notch that rotates in synchronization with the cam 12
Has a structure that shuts off the sensor. Reference numeral 2 is a current detection resistor for converting the motor current of the motor 11 into voltage, 3 is an amplifier for amplifying the voltage detected by the current detection resistor 2, and 4 is a threshold value for determining the presence or absence of a needle. It is a volume for adjustment. Reference numeral 5 is a CP for controlling the driving of the staple unit 1 and determining the presence or absence of staples.
U and 6 are EEPROMs for storing initial input parameters and the like of the staple unit, and 7 is a manual staple key for inputting a command to start stapling.

FIG. 2 is a detailed explanatory view of the staple unit 1.

Reference numeral 14 denotes a frame, on which the motor 11, the support shaft 15, the support shaft 19a and the like are pivotally supported. Reference numeral 12 denotes an eccentric cam, and the rotation of the motor 11 is transmitted via the pinion 17a, the two-stage gear 17b, and the gear 17c. Reference numeral 19 denotes a base portion of the swinging member, which is biased counterclockwise about the support shaft 19a by a spring (not shown). A roller 19b provided on the swing member 19 is in pressure contact with the eccentric cam 12, and causes the swing member 19 to swing by rotating the eccentric cam 12. Reference numeral 16 is a pressing roller that transmits the swing motion of the swing member 19 to the stapler 21. The roller 16 is a swing member 19
16 provided in an elongated hole 19c formed at the free end of
It is loosely fitted by a. Reference numeral 17c is a disk having a notch pivotally supported by the support shaft 15. The circular plate 17c rotates in synchronization with the eccentric cam 12, and is attached so that when the stapler 21 reaches the bottom end, the cam sensor 13 passes through the cutout portion.

In the above structure, when the staple request is input by the manual staple key 7, the CPU 5 sets the motor drive signal 101 to the H level and turns on the transistors TR1 and TR2. Then, the motor current I _M begins to flow in the motor 11 and rotates.

Detected voltage E _M detected by the current detection resistor 2
Becomes E _M = R _S × I _M. However, R _S is the resistance value of the current detection resistor 2.
The detection voltage E _M is input to the amplifier 3 through the voltage dividing circuit composed of the resistors R ₁ and R ₂ and the capacitor C ₁ and the low pass filter circuit. The input to the amplifier 3 is limited by the diodes D ₁ and D ₂ .

The amplifier 3 is a non-inverting amplifier circuit which keeps the input impedance high and the amplification degree thereof is determined by the resistors R ₃ and R ₄ . Further, the capacitor C ₂ has resistors R ₃ and R
_A low-pass filter circuit is configured with ₄ to prevent amplification of noise voltage.

FIGS. 3A and 3B are diagrams showing the relationship between the output CMOUT of the cam sensor 13 and the output IMOUT of the amplifier 3.

Point A in FIG. 3 is the timing of needle clinch. As shown in FIG. 4, point A is when the needle 41 is in a state of being completely pushed and bent by sandwiching the paper 43 by the staple blade 42 and the base 44.

The cam sensor output CMOUT rises at the timing point A of this clinch. CP
U5 is the output IM from the amplifier 3 when CMOUT rises.
The voltage input of OUT is A / D converted. By performing this A / D conversion a plurality of times and making the average value of them the final motor current that is calculated, the influence of external noise is reduced and the influence of current ripple due to motor characteristics is also reduced. ..

The solid line in FIG. 3B shows the waveform when there is no staple in the staple unit, and the one-dot chain line shows the waveform when there is a staple.
As is apparent from FIG. 3B, when the needle is clinched, the IMOUT 103 changes greatly depending on the presence or absence of the needle, and the presence or absence of the needle can be detected by this level difference. The threshold V _T for determining the presence / absence of the needle is set by the adjusting volume 4.

Further, the mechanism is designed so that the rising edge of CMOUT coincides with the clinch timing of the needle. However, in reality, depending on the precision of the parts and the variation during assembly,
It is difficult to completely match the two, and the timing can be adjusted in the CPU 5.

FIG. 5 is a flow chart for detecting the presence / absence of a needle by the CPU 5. After the power is turned on, the CPU 5 reads the clinch timing correction timer value from the EEPROM 6 (step 1). Next, the analog input of the adjusting volume 2 is A / D converted and stored in the RAM in the CPU as the threshold value V _T for determining the presence or absence of the needle (step 2). Next, the motor 11 is started and it is determined whether or not there is a falling input of CMOUT (step 3).

When the falling edge of the CMOUT 102 is input in step 3, the timer value read in step 1 is set in the timer (step 4), and the motor current from the amplifier 3 is set after waiting for the time up. A / D conversion of the indicated voltage output IMOUT is performed. A / D conversion of IMOUT is continuously performed a plurality of times (for example, 5 times), an average value thereof is calculated, and the obtained result is a voltage V _M indicating a motor current.
(Step 6, Step 7).

Next, the voltage V _M is compared with the threshold V _T read in step 2, and if V _M > V _T , it is determined that the stapler unit has staples, and if V _M <V _T, there is no staple. Then, a needleless alarm is output from a speaker, a display, or the like (not shown) (steps 8 and 9), and the process ends.

As described above, the presence or absence of the staple can be detected by observing the current state of the motor 11 that operates the stapler 21 when the stapler 21 is clinched. There is an effect that it can be simplified because a sensor or the like is unnecessary.

In the present embodiment, the rotation angle of the cam 12 is detected by the cam sensor 13 to determine the timing of inputting the voltage indicating the motor current.
Therefore, the voltage indicating the motor current may be input after a predetermined time from the start of the motor to detect the presence or absence of the staple of the stapler 21.

It is also possible to provide a large number of notches in the disk 17c for use as an encoder, and when the CPU 5 counts a predetermined number of pulses of the encoder, the input timing for inputting the voltage indicating the motor current may be set.

Further, in this embodiment, the instruction to start the stapling is inputted by the manual stapling key 7. However, when this sheet binding device is used in combination with a copying machine or the like, the stapling start instruction is inputted from the copying machine or the like. You can also do it.

[0026]

As described above, according to the present invention, the presence or absence of staples is determined according to the detection result of the current flowing through the motor for driving the staple means. There is an effect that it is not necessary to provide the apparatus, the apparatus can be downsized, and a low-cost sheet binding apparatus can be provided.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a sheet binding device according to an embodiment of the present invention.

FIG. 2 is a detailed explanatory view of the staple unit of FIG.

FIG. 3 is a diagram showing an output of a cam sensor 13 and an output of an amplifier 3 in FIG.

FIG. 4 is a diagram showing a state of the stapler 21 at point A in FIG.

FIG. 5 is a flowchart of the presence / absence detection of staples of the CPU 5.

[Explanation of symbols]

 1 Staple Unit 2 Motor Current Detection Resistor 3 Amplifier 4 Timer Adjustment Volume 5 CPU 6 EEPROM 7 Manual Staple Key 11 Motor 12 Eccentric Cam 13 Cam Sensor 17c Disc 21 Stapler

Claims (1)

Claim: What is claimed is: 1. A staple means for stapling a sheet with a staple, a motor for driving the staple means, a power supply for supplying a current to the motor, and a current flowing through the motor. A sheet binding device, comprising: a detection unit that detects the presence of a staple and a determination unit that determines the presence or absence of the staple according to the detection result of the detection unit.