JPS63206771A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent defective image formation by stopping the image formation when the detected value of a source voltage drops to a reference value or below and restarting the image formation when the detected value returned to the reference value. CONSTITUTION:A copying machine during execution of multiple copying under the control of a microcomputer 55 in a control circuit 5 completes the image formation on the paper under the image formation and prohibits the copying on the fresh paper when the source voltage to the copying machine drops. The copying prohibition is released and the copying with the remaining number of copies in the multiple copying is restarted when the source voltage returned to the prescribed level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to image forming apparatuses such as copying machines and printers, and particularly to problems such as paper jams, poor toner fixation, and
This is to prevent defective image formation due to image defects or the like.

2. Prior Art Conventionally, proposals have been made to reduce the adverse effect of a drop in power supply voltage on the copying operation of an electrophotographic copying machine.

FIG. 6 is a graph showing the temperature of the toner constant wear heater when performing multi-copying and - (multiple copying) when the power supply voltage drops.

As shown in the figure, when multi-copying (copying multiple sheets) is started (T-ta), if the IT power supply voltage is low, the temperature of the heat roller falls below the lower limit temperature at which defective fixing does not occur, and fixing occurs. Failures, low-temperature offsets, etc. may occur. This is because it is not possible to supply the heater with a current value sufficient to compensate for the temperature drop in the toner constant wear heater caused by heat being taken away by the copy paper.

For this reason, when the power supply voltage decreases, the number of copies per unit time is increased in order to reduce the amount of heat absorbed by the paper to be copied, in an attempt to prevent toner fixation failure (Japanese Patent Application Laid-Open No.
-121480).

On the other hand, in consideration of the fact that when the power supply voltage drops, the amount of light from the exposure device that exposes and scans the document decreases, power is cut off to the fixing heater, which consumes a large amount of power, to reduce the drop in power supply voltage to some extent. This is intended to suppress the reduction in the amount of light from the exposure apparatus (Japanese Patent Application Laid-open No. 135878/1983).

[Problems to be solved by the invention] However, when the power supply voltage drops, the number of copies per unit time is
Even if the IJ is limited, for example, the torque of the main motor that drives the photoreceptor drum etc. is reduced, so image defects or paper jams may occur due to poor rotation of the photoreceptor drum. Furthermore, even if the number of copies per unit time is limited, toner fixation problems may occur. On the other hand, cutting off the power supply to the fixing heater in order to maintain the level of voltage supplied to the optical device is only useful for a very short time.

If the energization is interrupted for a long time, the temperature of the fixing heater will drop, resulting in poor toner adhesion, low-temperature offset, and the like.

Therefore, if the power supply voltage drops below the specified level, especially when performing multi-copying (multi-copying), it is impossible to make normal copies for the desired number of copies by taking measures for each individual device that makes up the copier. It is difficult to complete the movement.

The present invention has been devised in view of the above circumstances, and prevents defective image formation when the power supply voltage drops when forming images on a plurality of paper surfaces. An object of the present invention is to provide an image forming device that enables image formation on a paper surface.

[Means for Solving the Problems] The image forming apparatus according to the present invention includes: an image forming means for forming an image on paper according to image information; and detecting the level of a power supply voltage supplied to the image forming means. a detection means for comparing a value detected by the detection means with a reference value; an input means for instructing the image forming means to form images on a plurality of paper surfaces; During visual and numerical image formation on the paper surface,
When the detected value becomes less than the reference value, image formation on a new paper surface is stopped, and when the detection value returns to the reference value or more, image formation on the remaining paper surface is restarted. and a control means for issuing a command to the image forming means.

Here, as the image forming means, for example, a means can be used which forms an electrostatic latent on a photoreceptor, develops it with toner, transfers it onto paper, and heats and fixes it to form an image. Examples of image forming means include copying machines based on analog or digital image information, or laser printers.

Further, the term "image formation on multiple paper surfaces" includes not only image formation on a plurality of paper sheets, but also cases where images are formed on the front and back sides of the same paper, and cases where images are formed overlappingly on the same side of the same paper.

Note that when an image is to be formed on a paper surface on which an image has already been formed, that paper surface is considered to be a new paper surface.

Further, in the control means, the reference value when stopping image formation and the reference value when restarting image formation may be the same or may be different.

[Example] Hereinafter, an example will be described with reference to the accompanying drawings, taking as an example a case where the image forming apparatus is a copying machine.

FIG. 1 schematically shows a copying machine according to this embodiment.

A photoreceptor drum 1 that can be rotated counterclockwise by a main motor M1 (AC synchronous motor) is arranged approximately in the center of the copying machine body, and around it are a main eraser lamp 2 and a sub charger 3. , sub-eraser lamp 4, main charger 5, developing device! 26, a transfer charger 7, a copy paper separation charger 8, and a blade type cleaning device 9 are provided. The photoreceptor drum 1 has a photoreceptor layer provided on its surface, and this photoreceptor is sensitized and charged by passing through the eraser lamp 2.4 and the charger 3.5, and receives image exposure from the optical system 10. .

The optical system 10 starts from below the original glass 16.
6 and a document presser 30 so that the image of the document can be scanned, and is composed of a light source (not shown), movable mirrors 11, 12, 13, a lens 14, and a mirror 15. has been done.

The light source and the movable mirror 11 are arranged at (v/
The movable mirror 12.13 is driven by the DC motor M3 so as to move to the left at a speed of (v/2 m). As the original m image is scanned by the optical system, the photosensitive drum 1 receives image exposure and forms an electrostatic latent image. Further, toner is attached to the cough electrostatic latent image in the developing device 6. In addition, when changing the copy magnification, use the stepping motor M4.
This causes the lens 14 to move on the optical axis and the mirror 15 to move and swing.

The document presser 30 is fixed to the copying machine with a hinge at one end, and the document presser detection switch 5 is activated when the document presser 30 is opened or closed.
W300 is turned on and off.

On the other hand, there are paper feed rollers 21 on the left side of the copying machine body.
．． A paper feed section 20.22 with a roller pair 24.25, a timing roller pair 26, and a conveyor belt 27 is installed.
, a fixing device 28, and a pair of discharge rollers 29 constitute a copy paper conveyance path.

Here, the timing roller pair 26 sends out the copy paper conveyed from the paper feed section with its leading edge aligned with the toner image forming area formed on the photoreceptor drum.

The fed-out copy paper is transfer chi 1? - The toner image is transferred by the roller 7, peeled off from the surface of the photoreceptor drum 1 by the separation charger 8, passed through the conveyor belt 27, and melted and fixed in the fixing bag 'm28, after which the toner image is transferred to the discharge roller. At 29, it was ejected from the aircraft.

(Description of the operation panel) An operation panel 100 as shown in FIG. 2 is installed on the upper front of the copying machine, and the operation panel 100 includes a print start key 102 for starting the copy operation, In addition to numeric keys 110 to 119 for entering the number of sheets, known key switches and the like are provided. Further, the round LED 103 is a warning indicator light that lights up when the power supply voltage falls below a predetermined level.

(Description of the control circuit of the copying machine) The copying machine described above has a plurality of C
It is controlled by the PU, and communication is performed between the CPUs as necessary. Of these, control iii associated with a drop in power supply voltage, which is a feature of the present invention, is processed by the first CF'U. Further, the other processes in the CPU are well known and will not be explained unless specifically required.

FIG. 3 is a circuit configuration diagram showing a power source voltage constant detection processing circuit according to this embodiment.

As shown in FIG. 3, the circuit includes a single-phase AC power supply 1, an AC drive circuit 3 that drives the toner constant wear heater 31 and the main motor M1, and a DC control circuit 5 that controls the AC drive circuit 3. It consists of a power supply voltage detection circuit 7.

In the AC drive circuit 3, the fixing 1jll! is performed by the 5SR (solid state relay) 32. 1i to energize the constant wear heater (lamp) 31 built in 128.
At the same time, the 5SR33 turns on the ACC synchronous mole M1 that rotates the photoreceptor drum 1. IJ III.

In addition, the DC control circuit 15 stably supplies DC5V.
It is composed of a C power supply 50 and a one-chip microcomputer 55 (incorporating an i-th CPU) which includes an A/D converter that receives DC power from the DC power supply.

In addition, the AC power supplied to the DC Power The Bly 50 is as follows:
The pressure is lowered by transformer N4.

The power supply voltage detection circuit 7 divides the voltage converted into low-voltage DC by the transformer 70 and the rectifying element 71 using resistors 73 and 74 to obtain a predetermined level of voltage.

The one-chip microcomputer 55 (hereinafter referred to as one-chip microcomputer 55) performs a power supply voltage detection process, and also controls the fixing heater lamp 31 via the SSR 32 to set the VA degree of the toner constant wear heater of the fixing device 28 to a predetermined value. Control so that the value is maintained. It also controls starting and stopping of the synchronous motor M1 via the 5SR33.

Here is the analog input port A of the one-chip microcontroller 55.
Nφ is connected to the voltage dividing point of the power supply detection circuit 7, and
The analog input boat ANI is connected to a thermistor that detects the temperature of the heat roller (heater for fixing) of the fixing device. Further, the output boat PAφ is connected to the 5SR32 via the driver IC, and the output boat PA1 is connected to the 88R33 via the driver IC. Further, the output boat PA2 is connected to the lighting circuit of the LEDIO3 via the driver IC.

Further, the document presser opening/closing detection switch 5W300 is connected to the input boat PBφ.

FIG. 4 is a flowchart showing an outline of the processing of the first CPU. As shown in FIG. 4, when the power is turned on, the first CPU sets the internal registers, various timers, etc. to the initial state, performs initial settings (S3), and starts the internal timer that specifies the time for one routine ($5). ). Next, a power supply voltage detection process is performed (87), then an input process ($9) and an output process (811) related to the copy operation are performed, and when the timer ends (S13), the process returns to S5. still,
Since the above S9.811 is well known, the explanation thereof will be omitted.

FIG. 5 shows the above-mentioned power supply type pressure detection process II! ! It is a flowchart which shows the detail of (87). First, the voltage level input to the analog signal input port ANφ is A10 converted to detect the power supply voltage level (S101). Note that the power supply voltage level can be detected by known methods such as peak level detection and area (integral value) detection.

Next, the detected value is compared with a predetermined level (8103).

When the detected value is less than a predetermined level, it is determined whether a copying operation is in progress (8105). Here, the term "during a copying operation" refers to the period from when the copying operation is started by inputting the print start key 102, etc. until the copying on the - side of the copying paper is completed. Note that whether or not the 11th copying operation is in progress is not limited to the above case, and can be determined from the standpoint of whether or not a defective copy is generated, as will be described later.

Further, whether or not a copying operation is in progress is determined based on transmissions from other CPUs (8105). $ if copying is in progress
Processes 107 to 5111 are performed. That is, multi-copy (
7 on condition that copying of multiple copies of the same original is in progress.
Lag 1 is set to "1" (S107.109). Here, flag 1 indicates that when the power supply voltage returns to a predetermined level or higher,
This is a flag that determines whether or not to restart multi-copy.

Also, copy stop processing is performed (S111). Copy stop processing here means that the copy paper currently being copied remains in the copier, requiring the effort to remove the paper, or
This is executed to prevent paper jams from occurring when copy protection is canceled. In addition, it is possible to prevent the occurrence of defective copies caused by interrupting the copying operation currently in progress. In other words, in this embodiment, for copying paper that is in the middle of copying, the copying operation is completed and the copied paper is removed. It refers to discharging to the outside of the machine.Also, when the power supply voltage level is less than a predetermined level, the warning indicator light LE[) 103 is lit (8118)
. In addition to lighting up the LED 103, a copy stop message may be transmitted to another CPIJ or a connected external device by communication.

On the other hand, if copying is not in progress <8105>, processing is performed to place the copying machine in copy prohibition (standby state) so that copying is not performed on a new copying surface (8113). here,
What does copy prohibition mean? ! This refers to a state in which a new copying operation is not started; for example, when copying is prohibited, input from the print start key 102 is not accepted by the CPtJ.

Next, by inputting the original presser detection switch 5W300, I
! A draft press, 1ul1 judgment of 130 1. (8115), 5
When it is determined that the document presser 30 has been opened by inputting W300, the flag 1 is set to O'' (8115.81
17). This is because if the document holder 30 is opened before the 'IIR' 1M pressure returns to a predetermined level or higher, the document on the document table is considered to have been removed. This is to avoid automatically restarting copying of uncopied valves.

In step 5103, when it is determined that the detected value exceeds a predetermined level, copying is prohibited (
5113) is released (8119) and LED10
Turn off 3. Also, when flag 1 is “1”, (8
123), start copying for the number of uncopied valves set in advance during multi-copy setting (S125)
, set flag 1 to 0'' (8127).

In the above embodiment, when the power supply voltage supplied to the copying machine decreases, the copying machine executing multi-copy completes image formation for the paper currently being created, and starts copying for new paper. It is placed in a prohibited state (standby state). For this reason, an image on a new sheet may be generated due to insufficient torque or step-out of the AC synchronous motor for driving the photoreceptor drum due to the power supply voltage, a decrease in the light amount of the exposure means, or a decrease in the current supplied to the constant wear heater. Defective, toner fixation failure,
This means that defective copies such as paper jams will not be made in advance. Furthermore, when the power supply voltage returns to a predetermined level, the copy prohibition is canceled and copying of the remaining number of multi-copy sheets is resumed. Therefore, according to the copying machine according to the above embodiment, once multi-copy is set, it is possible to carry out copying of the desired number of copies despite a drop in the Wi power supply voltage.

Further, in the above embodiments, the detection of the power supply voltage level and the comparison with a predetermined level are performed by software using a microcomputer, but they may also be configured by a hardware circuit.

In addition, in this embodiment, the amount of decrease ΔV1 in the voltage NtM voltage that causes a defective copy, and the amount of decrease ΔV1 in the power supply voltage that causes a non-maskable auto-reset on the microcomputer.
2, ΔV1<Δ■2. Therefore, the above processing becomes possible.

(Reference to Other Embodiments) In the above embodiment, copy prohibition is performed by processing to prevent new "copy operation" from starting, and copy stop processing is performed [? ! Regarding the copy paper during copying operation J, the "copying operation" is completed, and [copying operation J is understood as a series of operations from scanning the original to discharging the copy paper outside the machine. However, copy prohibition and copy stop processing are performed to prevent defective copies from occurring. Therefore, the process from transferring the toner image onto the surface of the copy paper to heating and fixing the toner can also be defined as the above-mentioned "copying operation." For example, by the timing roller pair 26,
Based on the time point when the copy paper is carried out to the photosensitive drum 1 side, it may be determined that before that time, copying is not in progress, and thereafter, it is determined that copying is in progress. in this case,
For example, it is determined whether or not a copying operation is in progress based on the time point at which a known timing clutch-on signal is output.

Next, in the embodiment described above, numeric keys 110 to 119
By setting a plurality of copies, multiple copies of the same original are commanded, and images are continuously formed on a plurality of paper surfaces.

However, continuous image formation on WI number of paper surfaces is possible in addition to the above case by using a known auto document feeder that automatically feeds the Wtm side of the document onto the Wt draft table. This process is also executed when paper is fed and a copy is made on the fed original. Furthermore, the present invention can be applied to cases in which double-sided copying and composite copying are performed by using a known paper refeeding unit to create an image again on a sheet of paper on which an image has been formed on one side.

[213'A of the Invention] As described above, according to the present invention, during image formation on a plurality of paper surfaces, 3111! If the voltage drops below a predetermined level, defective image formation will be prohibited on a new paper surface, and when the electric W voltage is restored, the prohibition of image formation will be canceled and the target number of paper surfaces will be This is to perform upward image formation. Therefore, when forming images on a plurality of paper surfaces, defective image formation that could occur conventionally when countermeasures are taken against fluctuations in the source voltage of each LFI device constituting the image forming means is not performed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing a copying machine according to this embodiment. FIG. 2 is a front view of the operation panel of the copying machine according to this embodiment. FIG. 3 is a circuit configuration diagram showing a power supply voltage failure detection processing circuit of the copying machine according to this embodiment. FIG. 4 is a flowchart showing an outline of the processing of the first CPU. FIG. 5 is a flowchart showing details of the power supply voltage detection process (S7). Figure 6 shows the constant values when performing multi-copy when the Ti1IIN pressure decreases. It is a graph showing the fixing temperature of f device. 28... Fixing device 55... One-depth microcomputer patent applicant Minolta Camera Co., Ltd. agent Patent attorney
Hirodo Okawa Patent Attorney Akio Maruyama Figure 3 Figure 4

Claims (2)

[Claims] (1) An image forming means for forming an image on paper according to image information, a detecting means for detecting the level of a power supply voltage supplied to the image forming means, and a detection value by the detecting means and a reference value. a comparison means for making a comparison; an input means for commanding the image forming means to form images on a plurality of paper surfaces; and a comparison means for instructing the image forming means to form images on a plurality of paper surfaces; When the detected value is less than the reference value, image formation on a new paper surface is stopped, and when the detected value returns to a reference value or more, a command is issued to the image forming means to restart image formation on the remaining paper surface. An image forming apparatus comprising: control means for controlling the image forming apparatus; (2) The control means, when the detected value becomes equal to or less than a reference value, instructs the image forming means to complete image formation on the paper surface being imaged. image device.