JPS6263966A - Image recorder - Google Patents

Abstract

PURPOSE:To prevent the omission of an image and solidification or fusion of a toner in a developing device by measuring the light emission or dimming time of an optical signal and correcting it in accordance with a printing dot mode and integrating and storing the operated value and sending a prescribed signal if stored contents exceed a preliminarily set reference value. CONSTITUTION:A picture signal fv is modulated by a modulator 1 and is inputted to a laser 2, and the light is emitted or dimmed in accordance with the picture signal fv, and a counter 3 operates AND between the image signal fv from the modulator 1 and the output from a clock generator 4 and divides the frequency of the result and outputs the division output. Meanwhile, a memory 5 stores the output of the counter 3 in an address B, and an arithmetic circuit 6 reads out contents of the memory 5 in synchronism with a pulse signal outputted from a frequency divider 10 and adds them to a memory 7 while integrating them. If contents of the memory 7 exceeds the reference value, a prescribed signal is outputted to a controller 9 and a toner replenishing signal S is sent to a display means. When the toner is replenished or a cartridge is replaced, memories 5 and 7 are reset. Thus, the omission of the image due to lack of the toner and solidification or fusion of the toner due to excess replenishment are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image recording apparatus that scans a photoreceptor with a laser beam to form a latent image.

[Conventional technology]

Devices that apply electrophotographic methods include electrophotographic copying machines and laser beam printers. Among these, laser beam printers are particularly in the spotlight as they are capable of high-speed image processing as computer terminal printers amidst the recent trend toward office automation. This system replaces the optical system of a conventional electrophotographic copying machine with a modulated laser beam as a terminal signal to obtain high-quality images through the same process as that of a copying machine.

FIG. 9 shows a layout diagram of the main processes around the photosensitive drum of such a laser beam printer.

In this figure, 11 is a photosensitive drum serving as an image carrier, and photosensitive layers 12. It is composed of a substrate 13. A primary charger 14 charges the photosensitive drum 11 uniformly. A laser beam 15 is scanned by a scanner (not shown). 1
6 is a developing device, and a doctor blade 17. Magnet roller 18. It is composed of a sleeve 19, and the inside thereof is filled with toner T serving as a developer. 2o is a pre-exposure lamp,
The entire surface of the photoreceptor drum 11 is exposed before charging.

A transfer paper guide 21 guides the fed recording paper. 22
A transfer charger transfers a toner image in which a latent image formed on the photoreceptor drum 11 is visualized onto recording paper by, for example, corona discharge. 23 is a cleaner, rubber blade 24
．． Magnet roller 25, screw 26. It is composed of a housing 27 and the like.

First, the photoreceptor drum 11, which has been uniformly charged by the negative charger 14, is irradiated with a laser beam 15 modulated in accordance with an image signal, and an electrostatic latent image is formed on the photoreceptor drum 1. . Subsequently, the photosensitive drum 11 undergoes a developing process by a developing device 16, and the latent image is visualized. Thereafter, a developed image is transferred by a transfer charger 22 to a recording paper (not shown) L introduced by a transfer paper guide 21. The transferred toner image is fixed on the recording paper by a fixing device (not shown), and is discharged to a discharge tray (not shown).

An example of an image formed in this manner is shown in FIG.

In this figure, 28 is a recording paper, and 29 is a transferred developed image.

On the other hand, the untransferred developing toner remaining on the photoreceptor drum 1.114- is removed from the surface of the photoreceptor drum 11 by the rubber blade 24, is attracted to the magnet roller 25, and is further removed from the housing 27 by the screw 26. It is stored in a toner collection box (not shown) that forms part of the toner collection box. Furthermore, the charge remaining on the photosensitive drum 11 is removed by the pre-exposure lamp 3o. In this way, the portion of the photoreceptor drum 11 from which the charge has been removed is sent to the first step, which is the primary charging step, and is used repeatedly.

In the process of irradiating the laser beam 15, the recording paper 2
An image in which a laser is irradiated on the photosensitive drum 11 in a portion corresponding to the visible image 29 on 8, the background other than the visible image 29 is irradiated with the laser, and the background other than the visible image 29 is not irradiated with the laser. A scanning method is used. This is because this method does not cause scan marks on the background image and is superior in reproducibility of images.

FIG. 11 is a diagram illustrating the behavior of the surface potential of the photosensitive drum 11 when forming a latent image.

In this figure, the vertical axis shows potential, and the horizontal axis shows each process step. Incidentally, the process steps are composed of a second charging step a, a laser exposure step S, a developing step C9, a transfer step d, a pre-exposure step e, and a second charging step f. Further, an example in which a phthalocyanate organic semiconductor is used for the photosensitive layer 12 of the photosensitive drum 11 is shown. Furthermore, the case where -order charging f is performed with negative polarity is shown.

The surface potential obtained by the primary charger 14 is the dark potential Vd
and the bright area potential Vh due to laser irradiation (V(1-
Vt+), which is converted into a latent image potential of about 550V with contrast.

As the toner T, a magnetic component developer is used.

The toner T in the developing device 16 is caused by mutual friction, the sleeve 19
It is charged by the contact friction of the doctor blade 17 or the like. The charged toner T is placed on the sleeve 19 with a uniform thickness by the doctor blade 17. The sleeve 19 rotates, and the toner T is attracted to the latent image area to be developed by the electric field between the potential of the developing bias voltage applied to the photoreceptor drum 11 and the sleeve 19 and the electrostatic latent image potential. . A portion of the latent image shown in FIG. 11 corresponding to the bright area potential Vh is developed.

For this purpose, the toner T must be charged to a polarity (in this case, negative) that develops a relatively high potential (bright area potential) Vh in the positive direction. In FIG. 12, toner T does not adhere to the negative potential portion of the dark potential Vd, and the bright potential Vd at the laser irradiation area near the ground potential.
h conceptually shows how negatively charged toner T adheres.

In such devices, conventionally, in order to prevent white spots on the image due to lack of developer, a sensor using a piezoelectric element or the like is placed inside the developer 16, and the amount of toner is controlled by changes in the output of the sensor. A method of detecting shortages is employed.

FIG. 13 is a diagram illustrating the structure of the developing device 16 shown in FIG. 9.

In this figure, 18 is a magnet roller, and four poles S I , N+ l S2 1 N2 are arranged on the inner circumference. The pole S1 serves as a developing pole, the pole N1 serves as a cutting pole, the pole S2 serves as a transport pole, and the pole N2 serves as a toner collecting pole. A high voltage power supply unit 30 applies a developing bias voltage to the sleeve 19. 31 is a piezoelectric element that changes its output voltage in accordance with changes in the weight of the toner T, compares this output voltage with a reference voltage (not shown) set in advance by a comparator 32, and determines whether the amount of toner is insufficient based on the comparison value. In this case, the display lamp 33 is turned on,
It is configured to notify the user.

[Problem that the invention seeks to solve]

However, in such a configuration, if the toner is concentrated at the position of the piezoelectric element 31, the indicator lamp 33 will not light up even if there is a shortage of toner because the weight applied to the piezoelectric element 31 is considerable, and the image will not be displayed. There was a drawback that white spots were generated. Conversely, if the toner T is concentrated at a position away from the piezoelectric element 31 in the developing device 16, even though the toner T is sufficiently filled, the piezoelectric element 31
Since the weight applied to the toner is too small, the indicator lamp 38 indicating toner shortage lights up. Therefore, in order to replenish the toner T, an oversupply state occurs, and the toner T solidifies in the developing device 16 and the image density decreases in that area, or the toner T is fused to the sleeve 19 and the image is ” Second, there were drawbacks such as unevenness.

In addition, in image recording apparatuses that employ the so-called process cartridge system, that is, a system that uses a disposable cartridge in which a drum, developer, cleaner, etc. are integrally formed, the method for detecting the remaining amount of toner as described above is Since there is no suitable one, there have been problems such as the inability to accurately detect the state of toner consumption.

Furthermore, with the process cartridge system, the lifespan of the developing device, drum, cleaner, etc. must be comprehensively judged and the appropriate replacement period must be indicated. There was no proper measurement method to display the lifespan of the product.

On the other hand, as in Japanese Patent Laid-Open No. 58-224383, a method has been proposed in which the number of dots forming an image area is accumulated and when the accumulated value exceeds a predetermined level, toner is replenished. However, this method is based on the assumption that the amount of toner consumed per dot is always constant, but the amount of toner consumed by one dot in solid black is different from the amount of toner consumed by one dot with a margin around it. Due to the edge effect, a single dot with a margin around it receives a stronger developing force and consumes a large amount of toner, resulting in problems such as the inability to accurately measure toner consumption.

This invention has been made to solve the above problems, and therefore it is possible to accurately determine the amount of toner consumed according to the form of printed dots formed in the scanning direction of the optical signal, and to determine the appropriate toner replenishment timing. It is an object of the present invention to provide an image recording device that can display images and prevent white spots in images and coagulation or fusion of toner in a developing device.

[Means for solving problems]

The image recording device according to the present invention includes a counting means for measuring the light emission or dimming time of an optical signal according to an image signal, a storage means for accumulating and storing the counted number of the counting means, and a storage means for accumulating and storing the counted number of the counting means. a calculation means for correcting the counted number according to the form of printed dots formed in the scanning direction of the optical signal; an integrated value storage means for integrating and storing the calculated value calculated by the calculation means; The apparatus is provided with signal sending means for comparing the stored contents with a preset reference value and sending out a predetermined signal when the reference value is exceeded.

[Effect]

In this invention, when the light emitting means counts the light emission or dimming time of the optical signal in accordance with the image signal, the counted number is accumulated in seven memory stages. The calculation means corrects the count number stored in the storage means according to the printed dot form in the scanning direction of the optical signal, stores the calculation result in the integrated value storage means, and sets the reference value set in advance. If the limit is exceeded, the signal sending means sends out a predetermined signal, for example a toner replenishment signal.

〔Example〕

FIG. 1 is a control block diagram of an image recording apparatus showing an embodiment of the present invention. Reference numeral 1 denotes a modulator that modulates an image input signal (image signal) fv into a laser input voltage. Reference numeral 2 denotes a laser, which emits or dims depending on the laser input voltage modulated by the modulator 1. 3 is a counter that measures the light emission time corresponding to the image signal of the laser. A clock generator 4 generates a predetermined pulse signal for synchronization with the image signal fv. A memory 5 serves as a storage means of the present invention, and stores the contents of the counter 3. 6 is an arithmetic circuit that corrects the contents of the memory 5; Reference numeral 7 denotes a memory which constitutes the settlement value storage means of the present invention, and stores the calculation results of the calculation circuit 6 while being integrated. A comparator 8 compares the contents of the memory 7 with a predetermined level. 9 is the signal transmission 7 of this invention
The entire device is controlled by a tiered controller. A frequency divider 10 divides the clock signal generated by the clock generator 4 into pulse signals of a predetermined frequency. Note that R5T is a reset signal that resets the memories 5 and 7. S is a toner replenishment signal that notifies the time of toner replenishment or cartridge replacement.

Next, FIGS. 2(a) to (d) and FIG. 3(a).

(b) The operation shown in FIG. 1 will be explained with reference to FIG.

FIGS. 2(a) to 2(d) are time charts for explaining the operation of the counter 3 shown in FIG. low level indicates laser dimming. FIG. 4B shows an AND output, which is a logical product of the image signal fυ and the pulse signal output from the clock generator 4. (C) of the same figure shows the counter output, in which the AND output is frequency-divided and output. Same figure (d)
indicates the output of the frequency divider 10.

First, the image signal fν is modulated by the modulator 1 and input to the amplifier 2. The light is emitted or attenuated in response to this image signal fV. As a result, the counter 3 is
), the image signal f from the modulator 1 and the output from the clock generator 4 are ANDed, frequency-divided, and output.

On the other hand, the memory 5 stores the output of the counter 3 at address B (X2), for example. The arithmetic circuit 6 reads the contents of the memory 5 in synchronization with the pulse signal output from the frequency divider 10, and adds the contents to the memory 7 while integrating the contents. This memory 7
The comparator 8 compares the integrated value with a preset reference value, and when the reference value is exceeded, a predetermined signal is output to the controller 9, and the controller 9 notifies you of the time to replenish toner or replace the cartridge. A toner replenishment signal S is sent to a display means (not shown).

When replenishing toner or replacing cartridges, memory 5
, 7 are reset by the reset signal R3T.

Next, the operation of the arithmetic circuit shown in FIG. 1 will be explained with reference to FIGS. 3(a), Cb) and FIG. 4.

FIGS. 3(a) and 3(b) are schematic diagrams illustrating the printing form of an image, and FIG. 3(a) shows an independent printing form in which non-printing dots are placed before and after the printing driver (A). FIG. 6B shows a continuous printing mode in which printed dots B to D are continuous.

FIG. 4 is a diagram illustrating the relationship between the toner consumption amount depending on the printing dot type, in which the vertical axis shows the toner consumption amount per dot, and the horizontal axis shows the light emission form of the laser 2. In addition, A-
D corresponds to the printed dots shown in FIGS. 3(a)-(b).

Printing driver existing in the independent printing form shown in Figure 3(a))
As shown in FIG. 4, the amount of toner consumed per dot is different between the printed dots A and the printed dots A to D which exist in the continuous printing form shown in FIG. 3(b). In other words, the electric field from the periphery is concentrated on the independent printing dots A and the printing dots B and D that form the ends of continuous printing, and the edge effect acts strongly.
More toner adheres than to printed dot C. Therefore, the arithmetic circuit 6 performs an arithmetic operation to correct the amount of toner consumption in accordance with the print dot form while accumulating the toner consumption amount in the memory 7.

Next, the correction calculation operation of the calculation circuit 6 shown in FIG. 1 will be explained with reference to FIG.

FIG. 5 is a flowchart illustrating the correction calculation operation of the calculation circuit 6 shown in FIG. In addition, (1) to (10)
indicates each step. Also, α is the second correction value (constant value)
It is obtained from the relative toner consumption amount of printing dot C and printing dot A, B, and D.

After setting the initial values of address A (Xi), address B (X2) of memory 5, and memory value M of memory 7 to fOJ, the laser 2 irradiates the printing dot immediately before the current printing dot. Determine whether it is in the on-J state 1) If YES, write address X of memory 5.
2 to ff1j, and set the first correction value G to [
'Set lJ (2). Next, it is determined whether the print dot immediately before the current print dot has not been printed, that is, whether the content of address xl is FOJ (3). Based on this judgment, the content of address X1 is 10.
In other words, in the case of a printing driver (A) as shown in FIG. , in the case of NO, only the first correction value G is added to the stored value M (5)
. Next, after passing the contents of address x2 to address x1, the contents of address x2 are reset (6). Subsequently, the comparator 8 sets the reference value M in advance.
7), and the reference value M1.
As long as the stored value M does not exceed the reference value M, the process returns to step (1), and when the stored value M reaches the reference value M1 or more, the toner replenishment signal S
The controller 9 outputs (8). On the other hand, step (
If the laser 2 does not irradiate the currently printed dot according to the judgment in 1), set the address X2 of the memory 5 and the first correction value M to 1.
0" (9) 6 Next, it is determined whether the contents of the address x1 are 1rIJ, that is, the printed dot A shown in FIG. 3(a) 9). If NO, step (6) If YES, proceed to (4) (10
). Note that after the toner replenishment signal S is output from the controller 9, the contents of the memories 5 and 7 are reset, and steps (1) to (lO) are repeated as described above. Furthermore, the above steps (1) to (10) are executed between 1 pulses output from the frequency divider 10, and the period of this pulse corresponds to the shortest light emission time of the laser 2. In this way, by repeating steps (1) to (10), the
) and (b) for the printing drivers A-D, respectively, "1+2αJ, fl+aJ, FIJ, rl
+αJ Camera E: It is added to the stored value M in step 7, and the accurate amount of toner consumption is measured according to the state of the surrounding printed dots.

FIG. 6 is a flowchart illustrating another correction calculation operation of the calculation circuit 6 shown in FIG. In addition, (1) to (1
6) represents each step. Also, α.

β indicates a correction value, correction value α indicates a relative difference in toner consumption between printing drum A) and printing drum C), and correction value β indicates a relative difference between printing dot C and printing dots B and D. be.

First, after setting the contents of addresses Xi, X2, and Judge whether it is in the J state from the contents of address
It is determined from the contents of address x2 whether the laser 2 will irradiate the print dots at the current time.
Judging from the contents of (10). If this judgment is YES, set the correction value G to ff'1 (12); if NO, set the correction value G to β1 (11). Then, set the correction value M to the memory value M in the memory 7. After setting G6) and passing the contents of address x2 of memory 5 to address XI,
The contents of address x3 are transferred to address x2, and address X3 is reset (7). Then, comparator 8
compares the reference value M1 set in advance with the stored value M in the memory 7 (8), and as long as the stored value M does not exceed the reference value M1, the process returns to step (1) and the stored value M exceeds the reference value M1. When the toner replenishment signal S is reached, the controller 9 outputs the toner replenishment signal S (9).

On the other hand, if the determination in step (2) is No, it is determined whether or not the laser 2 irradiates the subsequent printing dot at the current time (3). If this judgment is No, set the correction value O to the correction value G5), and if YES, set the correction value G to 11).
Set j (4) and proceed to step (6).

On the other hand, if the judgment in step (1) is NO, it is determined whether the laser 2 should irradiate the printing dots of the current printing dots13), and if No, proceed to step (3); if YES, Furthermore, it is determined whether or not subsequent printed dots at the current time are irradiated with the laser 2 (14). If this judgment is YES, the correction value G is set to 11+βJ (15), and if the judgment is No, the correction value α is set to the correction value G, and the process proceeds to step (6) (16).

By repeating steps (1) to (16),
Toner consumption can be accurately measured for consecutive printed dots.

Next, the operation of the arithmetic circuit 6 shown in FIG. 1 will be further explained with reference to FIG.

FIG. 7 is a characteristic diagram showing the relationship between developing bias potential and toner consumption, where the vertical axis shows the relative value of toner consumption;
The horizontal axis indicates the developing bias potential (V).

As can be seen from this figure, the developing bias potential is -400
V, -450V, -500V, the toner consumption when the developing bias potential is 1450V (
1(g)), the bias potential is 1400v
In the case of , the actual toner consumption is 0.8 times the toner consumption, and when the bias potential is 1500V,
The actual toner consumption is 1.2 times the toner consumption.

Therefore, when storing the toner consumption amount in the memory 7, the content is multiplied by a coefficient according to the bias potential and stored, thereby obtaining the toner consumption amount with high accuracy. It goes without saying that a more accurate toner consumption amount can be obtained by performing corrections that take into account temperature and humidity, drum potentials Vd and Vh, laser power, and the like.

In the above embodiment, the comparator 8 constantly compares the preset reference value D1 and the stored value D (toner consumption amount), and at point D shown in FIG.
(g))) We have explained the case where the toner replenishment signal S is output to perform the process, but two comparators and two memories are provided, and one comparator constantly compares the DI shown in Fig. 8 with the toner consumption. , toner consumption is El
If the controller 9 is configured to notify the user by sending out a toner replenishment notice signal when the toner replenishment is reached, the device can be operated continuously and the utilization efficiency of the device can be improved since more time is given for toner replenishment. Needless to say, it can be done. In FIG. 8, E2 indicates the capacity (g) of the developing device 16.

Further, although the above embodiments have been explained using a laser beam printer as an example, even if it is an electrophotographic printer using an LCD, LED, OFT, etc., or an image forming apparatus using a stylus method or a magnetic stylus method, it is possible to use a laser beam printer as an example. Any material that forms a latent image and can be visualized with a developer can be used.

In an apparatus having a toner hopper, the toner replenishment signal S can be used as a signal for replenishing toner from the hopper to the developing device.

Further, in the above embodiment, toner consumption due to latent image formation using an image scanning method has been described, but it goes without saying that the present invention can also be applied to an image recording apparatus using a background method that exposes a background other than an image. In that case, the counter 3 will count the dimming time of the optical signal.

Further, if the configuration is such that it is possible to detect when the toner is collected by the cleaner 23, it is possible to accurately notify the time to dispose of the collected toner.

〔Effect of the invention〕

As explained above, the present invention includes a counting means for measuring the light emission or dimming time of an optical signal according to an image signal, a storage means for accumulating and storing the count number of the counting means, and a storage means for accumulating and storing the counted number of the counting means. a calculation means for correcting the counted number according to the form of printed dots formed in the scanning direction of the optical signal; an integrated value storage means for integrating and storing the calculated values calculated by the calculating means; and an integrated value storage f stage. The toner consumption amount counted by the counting means can be printed on the printed dots. It can be corrected according to the configuration, the user can be notified of the toner replenishment time, and the toner can be replenished without excess or deficiency. Furthermore, it is possible to prevent white spots due to lack of toner and coagulation or fusion of toner due to excessive replenishment, which have been problems in the past. Further, the process cartridge type image recording apparatus has advantages such as being able to display an advance notice of the appropriate time to replace the cartridge.

[Brief explanation of the drawing]

FIG. 1 is a control block diagram of an image recording apparatus showing an embodiment of the present invention, FIGS. 2(a) to 2(d) are time charts explaining the operation of the counter shown in FIG. 1, and FIG. a)
, (b) is a schematic diagram explaining the printing form of an image, FIG. 4 is a diagram explaining toner consumption by printing dot form, and FIGS. 5 and 6 are corrections of the arithmetic circuit shown in FIG. 1. A flowchart explaining the calculation operation, FIG. 7 is a characteristic diagram showing the relationship between developing bias potential and toner consumption amount, FIG. 8 is a diagram explaining the relative relationship between toner consumption amount and memory, and FIG. 9 is a laser beam printer. FIG. 10 is a diagram showing the image output by the laser beam printer shown in FIG. 9, FIG. 11 is a diagram explaining the behavior of the surface potential of the photoconductor drum, and FIG. The figure is a conceptual diagram explaining the toner charging operation, and FIG. 13 is a diagram explaining the structure of the developing device shown in FIG. 9. In the figure, 1 is a modulator, 2 is a laser, 3 is a counter, 4 is a clock generator, 5 and 7 are memories, 6 is an arithmetic circuit, 8 is a comparator, and 9 is a controller. Figure 1 Toner Calendar V is No. 5 S Figure 2 Figure 3 Δ Figure 4 Figure 11 Figure 12 Figure 13

Claims (1)

[Claims] An image recording device that scans a photoreceptor drum with an optical signal modulated in accordance with an image signal to form a latent image, comprising: a counting means for measuring the light emission or dimming time of the optical signal in accordance with the image signal; A storage means for accumulating and storing the count of the counting means, a calculation means for correcting the count stored in the storage means in accordance with a print dot form formed in the scanning direction of the optical signal, and the calculation means The integrated value storage means integrates and stores the calculated value, and the content stored in this integrated value storage means is compared with a preset reference value, and if the reference value is exceeded, a predetermined signal is generated. 1. An image recording apparatus comprising: a signal sending means for sending out a signal.