JPH0241699A - Image processing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image processing device that uses a stepping motor as a drive source for a load such as an optical system for reading an image.

(Prior art) In this type of device, it is essential to drive the stepping motor by slowing it down.Also, since a large torque is required when starting the load, it is necessary to drive the stepping motor only during slow-up. Systems that allow a large amount of current to flow have already been proposed.

[Problems to be Solved by the Invention] However, in the above conventional example, a large amount of current is passed only during the slow-up period of stepping, and as soon as it is detected that the speed has reached a constant speed, the slow-up is started. However, in this case, depending on the circuit configuration of the motor drive circuit, the temperature of the stepping motor may rise and energy efficiency may decrease.

An object of the present invention is to solve such problems.

[Means for Solving the Problems] To this end, the present invention provides a driving means for driving a load by a stepping motor, a starting means for starting the stepping motor by slowing up, and a drive means for starting the stepping motor by slowing up.
The present invention is characterized by comprising a control means for controlling the load to a constant speed, and a means for switching the Zener voltage for eliminating back electromotive force applied to the stepping motor after a predetermined period of time has elapsed from the end of the slow-up.

[Function] According to the present invention, driving with good energy efficiency is possible by switching the Zener voltage for eliminating back electromotive force.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

Note that this embodiment will be explained using a copying apparatus as an example.

FIG. 1 is a sectional view of the entire copying apparatus according to this embodiment.

In FIG. 1, the drive system is divided into a main drive system that drives a paper feeding section, a conveyance section, a photoreceptor, and a fixing section, and an optical drive system that drives an optical system. An AC synchronous motor 25 is used as the main drive source, and a stepping motor (pulse motor) 2G is used as the optical drive source.

As the paper feeding method, feeding from the cassette 23 or feeding from the manual feed section 24 can be selected. When feeding paper from the cassette 23, the state is managed by a switch that detects the presence or absence of the cassette 23, a switch group 31 that detects the size of the cassette, and a switch 37 that detects the presence or absence of paper in the cassette. If an abnormality is detected, it is displayed on the display unit, which will be described later. The states of the manual feed guides 1 to 24 are managed by a switch 32 that detects the states, and when an abnormality is detected, it is displayed on a display section to be described later.

The photoreceptor 12 rotates clockwise in the figure. -Charger 13
The potential charged on the photoreceptor 12+ is exposed at an exposure position, which will be described in detail later, and developed in the developing unit 15. ) to transfer the image. After the transfer, residual toner is removed from the photoreceptor 12 by the cleaning unit 38, residual potential is removed by the pre-exposure lamp 16, and image formation is performed again. This process is repeated.

The transfer paper on which the image has been transferred rides on the conveyor belt of the conveyor unit 20 and is sent to the fixing unit 21. The fixing unit 21 is composed of a heat roller 35' having a temperature detecting element 35 such as a thermistor arranged on the surface thereof, and a roller having an elastic surface which is in pressure contact with the heat roller 35'. The heat roller 35' uses a halogen lamp as a heat source, and this halogen lamp is built in in the axial direction of the roller.

This Haloken lamp is controlled by a thermistor so that the surface temperature of the heat roller 35' reaches a predetermined temperature.

The paper that has passed through the fixing unit 21 is discharged from the fixing unit 21 by a paper discharge roller 22 and stacked on a paper discharge tray 39. Further, 34 is a paper discharge sensor that detects whether or not the transfer paper has passed through the fixing unit 21 normally.

As mentioned above, the drive source of the optical drive system is the pulse motor 26.
It is. The pulse motor 26 which is this drive source will later be used as the fifth motor.
As will be explained in detail in the drawings, the configuration is such that a completely different load is driven by operating the drive switching solenoid 27. 1
The two loads are the exposure lamp 4 and the first mirror 5. This is a unit that makes up the second mirror 6 and the third mirror 7, and the other load is a unit that makes up the zoom lens 8. These loads that do not require synchronous driving can be driven by a common drive source.

The apparatus according to this example has a multi-stage magnification selection function by controlling the position of the zoom lens 8 and speed control of the lamp systems 4 to 7 by the pulse motor 26 of the optical drive unit, and has a multi-stage magnification selection function by controlling the position of the zoom lens 8 and controlling the speed of the lamp systems 4 to 7. A function to automatically select the density using the optical sensor 40 that detects light, an external device (not shown)
A function to automatically select the copy magnification by connecting through a communication means, various countermeasure functions in the unlikely event that an abnormality such as a paper jam occurs, and a memory backup function that stores the magnification value for the number of remaining sheets, abnormality information, etc. In addition, a page quick copying function is provided by controlling the position of the exposure lamp 4 using the pulse motor 26, and a switch 36 that detects replacement of the developing unit 15 enables formation of a plurality of color images by replacing the developing unit 15. By providing this, it has a function to switch control depending on this state.

Next, the operation of this device will be explained.

FIG. 2 shows the operation panel of this device, which is arranged on the top surface of the device shown in FIG. When the I side of the power switch 51 is pressed, power is supplied to the tree mounting. At the same time, the power indicator lamp 5
2 is displayed lit.

The thermistor 35 of the fixing unit 21 detects that the heat roller 35' has not reached a predetermined temperature in the initial state after the power is turned on, and controls lighting of a fixing heater (not shown) as a heat source. When the power is turned on, the display on the operation panel is set as the standard mode, for example as shown below. The number of sheets display 59 displays "1°", the magnification display 67 displays equal magnification, and A of the automatic density adjustment display 76 is lit.

In addition, the display sections of star 1 to key 56 are displayed in red when the temperature inside the fixing unit 1- has not reached the fixing temperature, and when the temperature reaches the fixing temperature, the display switches to green and the copying operation starts. It is now possible to do so. Normally, all other indicators are off.

Note that the fixable temperatures of the fixing units 1 to 21 vary depending on the type of the developing unit 15, and the set temperature is changed by determining the type of the developing unit 15 using a switch 36 provided on the developing unit 15. Further, when the temperature needs to be lowered from a high state, a forced cooling means such as an internal cooling fan 28 is provided to quickly reach the fixing temperature.

The transmission and reception of these signals related to the operation panel, temperature control, and control operations for the optical drive system, etc. described below, are performed by the third
It is controlled by the one-chip microcomputer shown in the figure. Q in Figure 3! :tnOM.

The one-chip microcomputer Q has a built-in RAM, and this one-chip microcomputer Q executes control operations according to a microcomputer program whose basic configuration is shown in FIG.

Next, the operation of the optical drive system after power is turned on will be explained.

The exposure lamp systems 4 to 7 scan and move the original on the original glass 3 from the left end in FIG.
．． Second mirror 6, third mirror 7, zoom lens 8. Fourth
Mirror 9. The original is exposed to the photoreceptor 12 via the fifth mirror IO and the sixth mirror 11. In other words, set the starting point of movement to the left end. Set this position to the home position (
Below +1. P). This 11. To detect P)1. A P sensor 29 is provided. When the power is turned on, 11. When the P sensor does not detect the position of the exposure lamp 4, the control unit, for example, in the form of a one-chip microcomputer as shown in FIG.
side (known techniques can be used for forward/reverse rotation control of the pulse motor).

The start of the rotation control will be explained using FIG. 5. FIG. 5 shows an example of the configuration of a drive system in which two loads (optical system and lens) can be driven independently.

Here, ■ is a lamp drive gear 26' that is integrated with the boob to drive the optical load (exposure lamp systems 4 to 7).
is the motor output gear installed on the output shaft of the pulse motor, ■ is a switching gear that meshes with gear 26' and selectively meshes with gear ■ or ■ to switch the load, and 27 is connected to gear ■ via link ■. A solenoid is used to perform the switching operation, and ■ is a gear for driving the lens.

First, when the drive switching solenoid]-27 is in the off state (there is no force b'), the switching gear (2) moves in six directions by the spring pressure. As a result, the output of the pulse motor 26 is connected to the lamp drive gear (2) via the switching gear (2), and the exposure lamp units 4 to 7 are driven. During this gear connection, the rotation speed of the pulse motor 26 is controlled to be sufficiently lowered when the switching gear (1) and the lamp driving gear (2) are engaged.

Exposure units 4-7#<11. When located at P, the pulse motor 26 drives the zoom lens unit 8. In other words, the zoom lens position before the power is turned on is unknown. As described above, when the power is turned on, the same magnification value is selected as the standard mote. Therefore, an operation is performed to temporarily return to the reference position and set it to a predetermined position from that point.

Either the reference position above or the zoom lens home position (2,
) is called IP). Z,)IP that detects this position
A sensor 30 is provided.

The operation will be explained with reference to FIG.

When the drive switching solenoid 27 is turned on, the solenoid 2
Plunger 7 moves in direction b. Therefore, the force b' causes the switching gear (2) to move in the direction B against the spring force. Due to this movement, the switching gear (2) and the lamp drive gear (2) are disengaged. By further moving in the direction B, the switching gear (2) meshes with the lens drive gear (2). The rotation control when the gears are engaged is the same as described above.

The position of the zoom lens 8 is controlled within the range of the lens position from 200% magnification when located near the Z and HP sensor to a reduction rate of 50* when moved further to the right, with the Z and HP sensor as the reference position. It is carried out.

At the start of zoom lens driving, the operation is determined as follows depending on the states of Z and II P.

(1) When the position of the zoom lens 8 is detected by the Z and llP sensors.

(1) Move the -1-degree zoom lens 8 to the right and Z, 1-
Move it out of the range where it is not detected by the IP sensor and stop.

(1)-2 Move to the left side and stop after moving a predetermined distance from the point at which the II P sensor detected it.

If the P sensor does not detect the position of the zoom lens, execution starts from operation (1)-2.

The above operation is necessary control to prevent setting position errors due to backlash of gears.

After this, move the zoom lens 8 to the right again, and move it from the point where the zoom lens 8 leaves the Z and II P sensors to a predetermined position, that is, a position corresponding to the same magnification in the case of the standard mode setting. and stop. After this, the drive switching solenoid 27 is turned off. As a result, the switching gear (2) moves in the direction of meshing with the lamp driving gear (2) as described above. However, in order to achieve smooth meshing, it is necessary to rotate the switching gear (2) as already mentioned. At this point, the exposure lamp units 4 to 7 are II,
It's on page 29. Therefore, the pulse motor 26 rotates the exposure lamp units 4 to 7 in a direction to move them to the right. As a result, exposure lamp units 4 to 7 are 11
When it comes off the P sensor 29 (this means that the switching gear ■ and the lamp drive gear ■ have finished mating), the rotation is stopped, and it is rotated in the opposite direction again, and after detecting the H and P sensors 29, it is at the specified position. Stop.

The initial operation of the optical drive system and the fixing unit 21 explained above
By reaching the fixable temperature, preparation for the copying operation for wood binding is completed.

Next, the copying operation by feeding paper from the cassette 23 will be explained.

When the copy start key 56 is pressed, the transfer paper size data is generated by a manual signal from the switch group 31 that detects the cassette size, the number of sheets is set by the number key 54, and the magnification selection keys 81, 62, 64, 65, and 66 are generated. A copying operation is started based on magnification data and other data from various mote selection means.

When copy star 1 to key 56 are accepted, the display changes from green to red, setting key 54, magnification km 1.62,
Input of mode switching keys such as 64, 65, and 66 is prohibited. The main drive motor 25 starts rotating, and the paper feed roller 18
．． Photoreceptor 12. Transport unit 20. The driving force is transmitted to the fixing unit 21 and the like.

Further, at the time when the copy key 56 is received, the fixing temperatures of the fixing units 1 to 21 are switched depending on the cassette size data.

A paper feed solenoid (not shown) operates 0.5 seconds after the main drive motor 25 starts rotating, and the paper feed roller 17 rotates accordingly, moving the transfer paper in the cassette 23 in the direction of the paper feed roller 18. send out. The transfer paper feed amount of the paper feed roller 17 is controlled by the cassette 1 to size data. In other words, if the transfer paper is larger than a predetermined value, the amount of feed is increased. When the transfer paper reaches the paper feed roller 18, the transfer paper is fed by the paper feed roller 18 to the registration roller 19, and stops when it reaches the registration roller 19. Paper feed roller 1
A manual feed switch 33 installed between the registration roller 8 and the registration roller 19 detects the feeding state of the transfer paper.

At a predetermined timing until the transfer paper is sent along the paper feed path and reaches the registration rollers 19, the exposure lamp units 4 to 7 are allowed to start scanning the document. At this time, the exposure lamp is set to 11. It is located at a position detected by the P sensor 29. More specifically, during the initial operation or during the backward movement of the copy operation, the robot stops at a position that is a distance or backward movement corresponding to the selection magnification at that time from the position where the l(, P sensor is detected).

With the start of document scanning, the pulse motor 26, which is the optical system drive source, increases the pulse rate in the direction in which the exposure units 4 to 7 move forward (rightward) until the drive pulse rate reaches the drive pulse rate corresponding to the selected magnification value. increases gradually (called slow-up control). In other words, the 8-motion speed is gradually accelerated to reach the target speed. Although not particularly shown, the pulse motor drive circuit of this device adopts a constant current control method and has a configuration that allows the drive current value to be switched in multiple stages (two stages in the example) (the optical (Selected by the PB4 output signal of the drive pulse motor control signals)
.

In general, the characteristics of a pulse motor are such that the pull-in torque decreases as the pulse rate increases.

For this reason, a means for switching the constant current setting value is provided, and the current value is switched as necessary.

In this device, the set current is kept low during a relatively low pulse rate from the start of movement, and the set current value is increased from the point when the speed exceeds a predetermined value, and after reaching the target speed, the set current value is controlled to be increased. As time passes, control is implemented to lower the set current value again. This is mainly aimed at preventing noise, temperature rise, and step-out phenomena of the pulse motor.

Next, a method for forming a margin at the leading edge of the image and a method for aligning the leading edge with the transfer paper will be explained using FIG.

LED as a means to prevent toner adhesion in non-image areas
A light source such as a lamp or a fuse lamp is generally used to eliminate static electricity, but in this device, the same effect is achieved by controlling the voltage value of the grid 13' provided in the secondary charging unit 13. This is an important method in the current situation where it has become difficult to arrange a plurality of members around the photoreceptor due to miniaturization of devices. Exposure point and green
The distance between the gutter or the distance between the H and P sensor 29 and the document abutting position cannot be arranged sufficiently short compared to the aperture, so the magnification is adjusted from the time when the exposure lamp 4 starts moving to form a margin of 2 mm at the leading edge of the document. After a predetermined time period corresponding to the selected value, the grid is switched from the L level to a predetermined voltage. In other words, when the grid voltage is at the L level, no toner image is formed because the photoreceptor is not charged with potential, and an image is formed from the timing when the voltage is switched to the above-mentioned predetermined voltage. It forms a margin.

Specifically, regarding alignment of the leading edge of the image with the transfer paper, the distance C between the exposure point and the transfer section is made shorter than the distance C between the registration rollers 19 and the transfer section. For this reason, before the image at the leading edge of the document is actually exposed on the photoreceptor 12, it is necessary to re-feed the transfer paper waiting in the registration roller 19 section mentioned above and send it toward the transfer section.

In this apparatus, the time when the exposure lamp 4 starts moving and reaches the target speed is still 11. P sensor 29
has been detected. From the timing of passing the H, P sensor 29, the value obtained by dividing the value of distance +21 [11 by the speed according to the selected magnification is the value obtained by dividing the value of distance +21 [11] by the speed according to the selected magnification. This is the time required to do this, and let this time be X.

In addition, the value obtained by subtracting the time required for the image at the exposure point of the photoreceptor 12 to reach the transfer section from the time from when the registration roller 19 starts refeeding the paper until the transfer paper reaches the transfer section is y. Then, add the time required to feed the transfer paper 2 mm (2 mm ÷ 100 mm 0.02 sec...conveying speed - 100 mm/s) to this y. Calculate the above values using the following formula.

X - (:++ +0.02) = Z (sec)
In other words, 11. If the registration roller 19 is operated and the paper is re-feeded at the timing when the above formula value Z has passed after passing the P sensor 29, the transfer paper with a margin of 2 mm formed according to the selected multiplication factor 3 is generated. You can get the image.

The scanning distance of the exposure units 4 to 7 is set by moving a predetermined distance according to the size data, magnification data, etc. When the target position is reached, the pulse rate is gradually decreased (called slowdown control) and then stopped again. 11. Slow-up control and constant speed control are performed in the direction of the P sensor 29 to move backward. and 11
．． When the P sensor 29 is detected, slowdown control is performed to stop the exposure at a position corresponding to the selected magnification, and the exposure is stopped.

The manual copy operation is started when the manual feed sensor 33 detects the inserted transfer paper.

The main drive motor 25 starts rotating, and the paper feeding roller 18 also rotates accordingly. As a result, the inserted transfer paper is transferred from Lettuce 1 to Roller 1 by the paper feeding roller 18.
It is sent in 9 directions. Further, after a predetermined period of time has passed since the manual feed sensor 33 detects the transfer paper, the exposure lamp units 4 to 7 are allowed to start scanning the original. The subsequent operations of the exposure lamp system and the leading edge of the transfer paper are the same as in the case of cassette 1 to paper feeding, and will therefore be omitted. Next, the registration roller 19 is operated after the time X' required for the transfer paper to pass the distance between the manual feed sensor 33 and the transfer section after the rear edge of the transfer paper passes the manual feed sensor 33. Stop. Tatashi,
If the manual feed sensor 33 detects the next paper while counting the above X', the manual feed sensor 33 and the register 1 to roller 1
The operation of the registration rollers 19 is stopped when the time required for the transfer paper to pass through the distance between 9 and 9 has elapsed.

] 9 The document scanning distance is also controlled by the trailing edge signal of the transfer paper.

Figure 7 shows the one-depth micro combi coater Q shown in Figure 3.
An example of a configuration of a motor trie disposed between the pulse motor 26 and the pulse motor 26 is shown. Note that this figure shows only one phase for simplicity.

Here, Ql is a transistor for phase switching, Q
Reference numeral 2 denotes a transistor that performs switching in order to drive the pulse motor 26 with a constant current. ZDIZD2 is a zener diode for eliminating back electromotive force, Q3 is a 1 to run resistor for iodine of the zener diode ZD2, and J: rezener voltage v, +v2 becomes vl. R1 is a resistor for current detection. Then, the transistor Q3 is turned on by the Zener voltage switching signal for eliminating the back electromotive force from the one-chip microcontroller Q, and the Zener diode FZD2 is shorted.

Next, the control operation for the tree seed layer side will be explained along flowcharts 1 through 1 in FIG.

The processing procedure shown in FIG. 8 is started when the Coby Star key 56 of the copying machine shown in FIG. -7) Start (Sl). Since this optical system requires a large torque at the start of driving, a method is used in which the current value to the motor is set at a large value and the speed is gradually changed to slow it up to the target speed of 1~.

When this slow-up ends and the target speed is reached (
S3), start a timer set to a predetermined time (
R4). When the timer determines the predetermined time (S5),
The Zener voltage switching signal for eliminating the back electromotive force is turned on, and the Zener voltage is lowered together with the drive current (S6). Here, the reason why the current value and Zener voltage are lowered after a predetermined period of time has passed is to wait for the movement of the optical system to stabilize. By lowering the current value after it has stabilized, it is possible to keep the torque required for drying to a small value. When the optical system scans the image to the rear end (S7), it slows down and once stops the pulse motor. During slowdown, a large amount of current flows and the Zener voltage is also increased. This is because a large amount of torque is required during slow town. After stopping, the optical system is returned to the predetermined position (HP).

FIG. 9 is a diagram showing the speed of the pulse motor vs. time and the Zener voltage applied to the pulse motor for eliminating back electromotive force vs. time. 10 seconds after the end of the slow-up, it is shown that the Zener voltage has been lowered.

FIG. 10 shows another embodiment of the invention. Here, 82 is a first mirror stand that holds the lamp 4 and the first mirror 5;
83 is a second mirror that holds the second mirror 6 and the third mirror 7;
- The third mirror stand 81 is an optical wire that transmits the driving force of the motor 2B to move these optical systems. 8
0 is a Zener voltage switching point sensor for detecting a predetermined position of the optical system and switching the Zener voltage, and 84 is a signal plate provided in the optical system to be detected by the sensor 80.

In this example, switching of the Zener voltage is managed by sensor 80 rather than by a timer.

FIG. 11 shows an example of the Zener voltage switching control procedure according to this embodiment.

The operation will be explained according to flowchart 1 to FIG. 11.

First, when the copy start key 56 of the copying device is pressed (S11), the optical system driven by the pulse motor is started (512). Since this optical system requires a large torque at the start of driving, a method is used in which the current value to the motor is increased and the speed is gradually changed to slow up to the target speed. When the slow-up is completed and the target speed is reached (513), the vehicle is run at the target speed, and when the Zener voltage switching point detection sensor 80 detects that the optical system has reached the switching point (513).
14) Turn on the Zener voltage switching signal for eliminating back electromotive force and lower the Zener voltage (515). When the optical system scans to the rear end of the image (Si2), it is slowed down and the pulse motor is stopped once. Even during slowdown,
Zener voltage is set high. After stopping, the optical system is returned to the predetermined position HP (517).

Although the above embodiments have been described using a copying apparatus as an example, it goes without saying that the present invention can be similarly applied to other image forming apparatuses.

[Effects of the Invention] As described above, according to the present invention, by appropriately switching the Zener voltage for eliminating back electromotive force, energy efficiency can be improved and torque margin can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a copying apparatus according to an embodiment of the present invention, FIG. 2 is a plan view showing an example of the configuration of the operation panel of the apparatus shown in FIG. 1, and FIG. FIG. 4 is an explanatory diagram showing an example of the basic configuration of the program of the one-deep microcomputer shown in FIG. 3. FIG. An explanatory diagram showing an example of the configuration of a switching system for switching. Figure 6 is a diagram for explaining the formation of a margin at the leading edge of an image and how the leading edge overlaps with transfer paper. Figure 7 is an example of a configuration of a pulse motor drive circuit. 8 is a flow chart 1-1 showing an example of a control procedure according to an embodiment of the present invention. FIG. 9 is an explanatory diagram showing the relationship between speed and Zener voltage with respect to time of the pulse motor. The figure is a block diagram of another embodiment of the present invention, and FIG. 11 is a flowchart 1 to 1 showing an example of its control procedure. 4... Exposure lamp, 5, [i, 7, 8, 9, 10.12... Mirror 12
... Photoreceptor, 13 ... - Charger, 14 ... Transfer unit, 15 ... Development unit, 20 ... Conveyance unit, 21 ... Fixing unit, 26 ... Pulse motor, 27... Drive switching solenoid, 29... I/P sensor, 80... Zener voltage switching point detection sensor. Ward C Liang Ward ■ School 83 moat 2 recruitment 3 mirror stand

Claims (1)

[Scope of Claims] 1) A driving means for driving a load by a stepping motor, a starting means for starting the stepping motor by slowing up, a control means for controlling the load to a constant speed after the end of slowing up, and slowing up. An image processing apparatus comprising: means for switching a Zener voltage for eliminating back electromotive force applied to the stepping motor after a predetermined period of time has elapsed since the end of the process.