JP2661941B2 - Image recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image recording apparatus such as a copying machine having a transfer belt device for transporting transfer paper to a transfer position.

2. Description of the Related Art In a color copying machine or the like having a plurality of recording devices and a transfer belt device for transporting transfer paper to a transfer position of each recording device, transfer is performed for paper removal processing when a paper jam or the like occurs. 2. Description of the Related Art It has been practiced that a belt is formed so as to be movable between an operating position in contact with a photoconductor and a release position away from the photoconductor.

When the next image formation is performed with the transfer belt moved to the release position for work such as paper removal, the transfer paper is not properly conveyed because the transfer belt is not at the predetermined position, and the paper is again jammed. turn into.

In order to solve this problem, when the transfer belt is at the release position, it is necessary to detect the fact and prevent the next image forming process from being performed. For this purpose, it is necessary to provide a dedicated sensor for detecting the transfer belt. Providing a dedicated sensor has the disadvantage that the cost increases accordingly.

If a special sensor is not installed to prevent cost increase and the attention of the operator is used, it is difficult to prevent the transfer belt from being released and proceeding to the next image formation with the transfer belt released. There is a problem that it takes time and effort.

An object of the present invention is to solve the above-mentioned conventional problems and to provide an image recording apparatus capable of confirming that a conveyor belt has returned to an operation position after a work such as a paper jam without providing a dedicated sensor. It is intended to provide a device.

In order to achieve the above object, the present invention enables one of the rollers around which a transfer belt is wound to be movable between an operation position where the transfer paper contacts the photoconductor and a release position where the transfer paper is separated from the photoconductor. A signal from a sensor for controlling the toner density, which is disposed close to the transfer belt in the vicinity of the transfer belt, and a signal from an open / close detection switch of an open / close door of the image forming apparatus are input to the door switch. A control device for detecting whether or not the transfer belt is released by comparing a signal from the sensor with a preset reference value when the switch is ON and when the door switch changes from ON to OFF. It is characterized by.

The configuration and operation of the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows an example of an image recording apparatus to which the present invention is applied. This example is based on a scanner unit 1 for reading a document, an image processing unit 2 for electrically processing an image signal output as a digital signal from the scanner unit 1, and image recording information of each color from the image processing unit 2. And a printer unit 3 for forming an image on copy paper.
The scanner unit 1 has a lamp 5 for scanning and illuminating a document on a document table 4, for example, a fluorescent lamp. The reflected light from the original when illuminated by the fluorescent lamp 5 is reflected by the mirrors 6, 7 and 8 and is incident on the imaging lens 9. The image light is imaged on the dichroic prism 10 by the imaging lens 9 and split into, for example, light of three wavelengths of red R, green G, and blue B, and a light receiver 11 for each wavelength light, for example, a CCD 11R for red, Light is incident on the CCD 11G for green and the CCD 11B for blue. Each of the CCDs 11R, 11G, and 11B converts incident light into a digital signal and outputs the digital signal. The output is subjected to necessary processing in the image processing unit 2 to record color information of each color, for example, black (hereinafter abbreviated as BK), The signals are converted into recording signals of each color of yellow (abbreviated as Y), magenta (abbreviated as M), and cyan (abbreviated as C).

FIG. 1 shows an example in which four colors of BK, Y, M, and C are formed, but a color image can be formed with only three colors. In that case, the number of recording devices can be reduced by one set compared to the example of FIG.

The signal from the image processing unit 2 is input to the printer unit 3, and the laser light emitting devices 12BK, 12C,
M, sent to 12Y.

In the example of the figure, the printer unit includes four recording devices 13C, 13M,
13Y and 13BK are arranged side by side. Since each recording device 13 is made of the same components, the recording device 13C for C will be described for the sake of simplicity.
M, 13Y, and 13BK are omitted. The same reference numerals are given to the same parts for the respective colors, and in order to distinguish the configuration of each color, the reference numerals are added to the reference numerals indicating the respective colors.

The recording device 13C has a photoconductor 14 outside the laser beam emitting device 12C.
C, for example, having a photosensitive drum. A photoreceptor 14C is provided with a charging corona discharger 15C, an exposure device using a laser beam emitting device 12C, a developing device 16C, a transfer charger 17C, and the like, similarly to a known copying device.

The photoreceptor 14C is rotated by a motor and uniformly charged by a charging corona discharger 15C, and then forms a latent image of a cyan light image by exposure by a laser light emitting device 12C,
The developed image is formed by the developing device 16C. Paper feed roller 1
The transfer paper supplied from the paper supply unit 19, for example, one of the two paper supply cassettes by 8, is sent to the transfer belt 21 with the leading ends thereof aligned by registration rollers 20 and at the same timing. The transfer paper conveyed by the circulating transfer belt 21 is sequentially sent to the photoconductors 14BY, 14Y, 14M, and 14C on which the visualized images are formed, and the visualized images are superimposed and transferred under the action of the transfer charger 17, and are fixed. The sheet is fixed by 22 and is discharged by a discharge roller 23.

The transfer paper can be accurately conveyed at the speed of the transfer belt by electrostatically adsorbing to the transfer belt 21.

The transfer belt 21 is rotated around a tension roller 24, a driving rubber roller 25, and a driven roller 26.

A photo sensor 28 is disposed near the driven roller 26 and above the transfer belt 21. Photo sensors 28 are recording devices 13C, 13M,
Used to read the density of the standard pattern for toner replenishment control transferred by 13Y and 13BK sequentially and send it to the control unit to control the toner density and to detect whether the transfer belt has been released or not. Things.

A metal plate 29 is provided at a position facing the photo sensor 28 across the transfer belt 21 in order to make it easy to read a standard pattern for toner supply control. Transfer belt 21
The driven roller 26 can be moved to the release position when the driven roller 26 moves down, for example, by moving the driven roller 26 side down about the axis of the driving rubber roller 25.

First, the function of toner supply control of the photo sensor 28 will be described.

 FIG. 2 shows a control section of the color copying apparatus.

In the figure, reference numerals 30 and 31 denote light-emitting diodes and phototransistors 32 constituting a photodiode 28, a CPU (microcomputer), 33 a driver, 34 a variable volume, 35 and 36.
Is a resistor, and 37 is a capacitor. Phototransistor 31
For example, 5 V is applied, and the reference voltage is adjusted by the variable volume control 34. This reference voltage is
Is the output voltage value due to the reflected light. The CPU 32 takes in signals from the photo sensor 28 and the like of the printer unit 3 and controls each unit of the printer unit 3, and FIG. 3 shows a part of the processing flow.

The CPU 32 sends the BK signal from the image processing unit 2 to the laser beam emitting device 12BK of the recording device 13BK separately from the signal for forming the BK record by the original.
Is sent. Therefore, after the photoreceptor 14BK is uniformly charged by the charging corona discharger 15BK, a latent image of the standard pattern is formed outside the original image forming area by exposure by the laser beam emitting device 12BK, and is developed by the latent image device 16BK. Is transferred to the transfer belt 21. CP
U32 is similarly Y, M, and M, depending on the original, from the image processing unit 2 to the laser beam emitting devices 12Y, 12M, and 12C of the recording devices 13Y, 13M, and 13C.
The standard pattern signals for toner replenishment control of Y, M, and C are sequentially transmitted separately from the signal for recording formation of C, and the photosensitive members 14Y and 14
A latent image of the standard pattern is formed on M and 14C, and is transferred to the transfer belt 21 after development by the developing devices 16Y, 16M and 16C. Therefore, as shown in FIG.
The Y, M, and C standard patterns 38BK, 38Y, 38M, and 38C are transferred to a predetermined position at predetermined intervals in a row in the rotation direction.

Assuming that the color copying apparatus performs area gradation with a basic matrix of 4 × 4, a standard pattern is formed as shown in FIG. 5 by repeating the 4 × 4 pattern. Which dot of 4 × 4 = 16 dots is black or white is related to the detection sensitivity.
A spot type having an area ratio of 25% in FIG. D is used.

Standard patterns on the transfer belt 21 then CPU32 is photosensor 28 after taking the output signal V _SG when the photosensor 28 to measure the background portion density of the metal plate 29 via the transfer belt 21
Output signal V when measuring the concentration of 38BK, 38Y, 38M, 38C
_SPBK, V _SPY, V _SPM, incorporation of V _SPC, and compared with a reference value to calculate the V _SPBK / V _SG, smaller than greater than V _SPBK / V _SG is the reference value (BK toner concentration reference value ) A BK toner replenishment signal is output to supply a certain amount of BK toner from the BK toner replenisher to the developer in the developing device 13BK.

Then CPU32 compares the reference value seeking _{V SPC / V SG, V SPC} /
If V _SG is larger than the reference value, a C toner replenishment signal is output to supply a certain amount of C toner from the C toner replenisher to the developer in the developing device 13C.

Similarly, the CPU 32 calculates V _SPM / V _SG and compares it with the reference value,
_{If SPM} / _VSG is larger than the reference value, an M toner replenishment signal is output to supply the developer in the developing device 13M with M toner from the M toner replenisher.
A certain amount of toner is supplied.

Further, the CPU 32 obtains V _SPY / V _SG and compares it with a reference value to obtain V _SPY / V _{SG.
If SPY} / _VSG is larger than the reference value, a Y toner replenishment signal is output to supply the developer in the developing device 13Y with Y toner from the Y toner replenisher.
A certain amount of toner is supplied. FIG. 6 shows an example of the waveform of the output signal of the photo sensor 28. FIG. 7 is a timing chart of the printer unit 3. When the print switch is turned on, the CPU 32 causes the drum motor to rotate the photosensitive member 14 and the transfer belt motor to rotate the drive roller 25, and the laser light emitting devices 12BK, 12Y, 12Y by the first to fourth vertical synchronization signals.
The image light of each color is exposed to M and 12C, and the standard pattern of each color is further exposed to turn on the photosensor.

Next, control for detecting whether or not the transfer belt 21 is released by the photo sensor 28 and prohibiting recording by the image recording apparatus will be described.

FIG. 8 shows the positional relationship between the photosensor 28, the transfer belt, and the white plate. Transfer belt when the in contact usually the photoconductor, the distance d between the photosensor 28 is in the close distance d _1, for example 3.5 mm (the position indicated by a broken line in the figure). At this time, the photo sensor 28 detects the reflected light from the metal plate, and shows an output waveform as shown in FIG. 9A.

On the other hand, when a paper jam or the like occurs, the transfer belt is released to remove the jammed transfer paper, and when the transfer belt is lowered, the distance d between the transfer belt and the photo sensor 28 is a long distance d ₂ , for example, about 10 mm (the position indicated by the solid line in the figure). )become. The output of the photo sensor 28 at this time is as shown in FIG. 9B.

FIG. 10 is a flowchart relating to a control performed by the CPU 32 to inhibit the recording of the image recording apparatus depending on whether or not the transfer belt 21 is released.

The photo sensor 28 is used for toner supply control during image recording.

Since the transfer belt 21 is released when the door of the image recording apparatus is opened for a paper jam or the like, it is determined whether the transfer belt has been released once at this time and after the door is closed. The photo sensor 28 is used to perform this.

As shown in FIG. 2, the CPU 32 is connected to a door switch 38 for detecting whether the door is opened.
The opening / closing of the door is detected by the door switch 38, and the door open flag is turned ON when the door is opened. When the door is open, stop the image recording device even during image recording,
Prohibit recording.

At this time, since the photo sensor 28 is not used for toner supply control, it is used for detecting the release of the transfer belt.

The CPU 32 receives the output of the photo sensor 28 and compares it with a preset reference value V _BELT stored in advance. V _BELT is, for example, about 3V.

When the output voltage V _{BELT is} larger than the photosensor 28 output voltage as shown in FIG. 9A, it indicates that the transfer belt is approaching the photosensor 28, that is, in contact with the photoconductor. Therefore, at this time, the CPU shifts to another control after turning off the transfer belt release LED. However, when the output voltage V of the photo sensor is
As shown in FIG. B, when it is smaller than V _BELT, it indicates a state where the transfer belt 21 is separated from the photosensor 28, that is, a state where the transfer belt is moved to the release position. At this time, the CPU 32 turns on the transfer belt release LED 40, informs the operator that the transfer belt has been released, and inhibits image recording.

Next, when the door is changed from the open state to the closed state, the release of the transfer belt is detected only once when the door is opened and closed by checking whether the door open flag is ON. .

When the door switch 38 indicates that the door is closed, the door open flag is ON when the door is opened and closed. Therefore, the door open flag is turned OFF and the output voltage V of the _photo sensor 28 is changed to V _BELT Compare with If V> V _BELT, the transfer belt release LED 40 is turned off because the transfer belt is in contact with the photoconductor.

In this case, the door is closed when the door open is checked again, and the door open flag is also OFF.

Since the transfer belt release LED 40 is also OFF, image recording is possible, and the CPU 32 executes image recording control.

When V ≦ V _BELT , since the transfer belt 21 is at the release position, the transfer belt release LED 40 remains ON, and the image recording continues in the prohibited state.

In this case, to perform image recording, open the door again, and move the transfer belt 21 to a position where the transfer belt 21 contacts the photosensitive member.
Move 26. When the driven roller 26 is set to the operating position and the door is closed, the transfer belt release check is performed only once, and the transfer belt release LED 40 is turned off. As a result, when the door is closed, an image can be recorded.

According to the present invention, the image cannot be recorded unless the transfer belt is set to the operation position. Therefore, the transfer paper is not conveyed while the transfer belt is in the released state, and the paper is not jammed. Eliminating time-consuming paper removal operations is eliminated.

An example of using a sensor for toner replenishment control as a sensor has been shown, but a sensor for paper jam detection and other sensors necessary for other appropriate functions are also used as sensors for detecting whether the transfer belt is released. can do.

According to the present invention, a toner pattern is formed on a transfer belt, and the transfer belt is set to an operating position in contact with a photoconductor or released to a release position by a sensor for reading the pattern and performing toner supply control. If this signal is used to control whether image recording is activated or inhibited, image recording can be performed with the transfer belt released, and paper jams can be avoided. In addition, no special sensor is required to check the release of the transfer belt, and the cost can be reduced. The workability has also been improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a color copying machine to which the present invention is applied, and FIG.
Fig. 3 is a schematic diagram of the control unit, Fig. 3 is a control flowchart of the control unit, Fig. 4 is a schematic perspective view showing a standard pattern image on the transfer belt, and Fig. 5 is an example of a standard pattern when performing matrix area gradation. FIG. 6 is a diagram showing an example of a waveform of an output signal of a photosensor, FIG. 7 is a timing chart of a printer section, and FIG. 8 is an operation of a transfer belt. FIG. 9 is a diagram showing the output waveform of the photo sensor, FIG. 9 is a diagram showing the output waveform of the photo sensor, b is a diagram showing the time of release, and FIG. 10 is a diagram showing whether or not the transfer belt is released. 5 is a flowchart for controlling image recording by detecting the image data. 12 Laser light emitting device (exposure means) 13 Recording device 14 Photoreceptor 15 Corona discharger for charging 16 Developing device 17 Transfer device 21 Transfer belt 26 Driven roller 28 Photo sensor (sensor) 32 CPU 38 Door switch

Claims (1)

(57) [Claims] 1. A photoreceptor, a charging corona discharger for uniformly charging the surface of the photoreceptor, and an exposure unit for projecting image light corresponding to recorded information on the photoreceptor to form a latent image. A plurality of recording devices each having a developing unit for developing the latent image on the photoconductor and a transfer unit for transferring a visual image on the photoconductor to transfer paper; In an image recording apparatus that sequentially transfers a transfer paper to a transfer position by a transfer belt and superimposes and transfers a visible image, an operation position where one of the rollers around which the transfer belt is wound contacts the transfer paper with the photoconductor, and transfers the transfer paper from the photoconductor. A signal from a sensor for controlling the toner density, which is disposed near the roller and in close proximity to the transfer belt, is provided so as to be movable between the release position and the opening / closing door of the image forming apparatus. Input the signal from the open / close detection switch When the door switch is ON and when the door switch changes from ON to OFF, a control device for comparing the signal from the sensor with a preset reference value stored in advance to detect whether or not the transfer belt is released is provided. An image recording apparatus, comprising: