JP3486500B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of image forming apparatuses used in laser beam printers, laser beam FAX, and the like.

[0002]

2. Description of the Related Art FIG. 13 is a sectional view showing the structure of a conventional laser beam printer.

In FIG. 1, 1 is a laser beam printer, 2 is a photosensitive drum, 3 is a scanner unit, 4 is a mirror, 5 is a charger, 6 is a developing device, 7 is a transfer roller, 8 is a drum cleaner, and 9 is paper. Cassette, 10 is a paper feed roller, 1
3 is a fixing device, 14 is a paper ejection sensor, 15 is a paper ejection tray, 1
6 is a top sensor, 40 is a printer controller, 25
Is a CPU.

With this configuration, when the print signal from the printer controller 40 is received, the CPU 25 drives the paper feed roller 10 to feed the paper from the paper cassette 9. In parallel with this, a laser (not shown) and a scanner motor (not shown) in the scanner unit 3 operate. Then, in synchronization with the approach of the fed paper to the photosensitive drum 2, a video signal is transmitted from the printer controller 40, the photosensitive drum 2 is scanned with laser light, and a latent image corresponding to the video signal is formed on the photosensitive drum. 2 is formed on. After that, toner is attached by the developing device 6 to form a visible image, which is transferred to the paper being conveyed by the transfer roller 7, fixed by the fixing device 13, and output as a hard copy.

Conventionally, in this configuration and operation, the CPU
Reference numeral 25 denotes a top sensor 16, a paper discharge sensor 14 and the like to detect the leading edge and the trailing edge of the paper, and a door sensor (not shown) to detect a door open. For example, the printer door is opened during printing, or a paper feed error occurs. If the conveyance of the paper is delayed or the conveyance of the paper is stopped due to the skew, the driving of the conveyance rollers is stopped to make a jam, and the status is transmitted to the print controller 40. The same applies when paper is present in the machine at power-on.

Conventionally, the above-mentioned operation is configured to be possible.

[0007]

However, in the conventional example, there are problems that deterioration of the photosensitive drum and image fading of the print sample occur due to repeated printing with the cartridge integrated with the photosensitive drum.

The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to prevent deterioration of the quality of an image formed and recorded on a recording medium by coping with changes in the state of the photosensitive drum and the state of the print sample image. An object of the present invention is to provide an image forming apparatus using a photosensitive drum integrated cartridge.

[0009]

The image forming apparatus of the present invention achieves the above object by the following constitution.

[0010] (1) An image forming apparatus for forming an image on a photosensitive body and mounting the cartridges with built-in non-volatile memory recording medium, before hear cartridges lead or the printing number of sheets used from the non-volatile memory and It has a read / write means for writing to the non-volatile memory, and corresponds to the read from the non-volatile memory, and an image to be formed
An image forming apparatus having a switching means for switching and forming in point symmetry .

(2) The nonvolatile memory is EEPROM
The image forming apparatus according to (1) above, wherein the image forming apparatus is M.

[0012]

[0013]

[0014]

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The image forming apparatus according to the present invention has a function of E in order to extend the life of the photosensitive drum by repeating printing and to keep the quality of the print sample constant.
When a photosensitive drum-integrated cartridge having a built-in EPROM is mounted and the number of prints of the same cartridge is stored in the EEPROM, when a certain number of prints is reached, 1. Increase the drive torque of the motor.

2. Switch images to point symmetry.

Further, as a means other than the above, by storing the number of cleanings of the photosensitive drum, when a predetermined number of cleanings is reached, Change the developing voltage.

4. Switch the laser light intensity.

The details of the above embodiment will be described with reference to examples.

[0020]

The embodiment of the present invention is an image forming apparatus in which a photosensitive drum-integrated cartridge having a photosensitive drum and a non-volatile memory is mounted, and an image is formed and recorded on a recording medium by printing using the photosensitive drum-integrated cartridge. It has a read / write means for reading the number of sheets from the non-volatile memory or writing to the non-volatile memory, and has a basic configuration to control the apparatus main body in response to the reading from the non-volatile memory.

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3 and 14. FIG. 14 shows a conventional example.

FIG. 1 is a flow chart of the first embodiment, and FIG. 2 is an explanatory view of changes in the drive torque of the cartridge and the drive torque of the motor according to the increase in the number of prints in the first embodiment. FIG. 3 is a block diagram of a main part of the first embodiment. FIG. 14 is an explanatory diagram showing the relationship between the drive torque of the cartridge and the drive torque of the motor due to the increase in the number of printed sheets in the conventional example.

The drive torque of the cartridge increases as the remaining amount of toner decreases. Therefore, as shown in FIG. 1, when the number of used cartridges is small, the drive torque of the motor is low. Then, when the number of sheets increases to a certain number, the drive torque is increased. That is, the drive torque of the motor is determined according to the life of the cartridge, and when the number of prints is small, the drive torque of the motor is lowered.

Means for reducing the drive torque of the motor will be described with reference to FIG.

In FIG. 3, 31 is a CPU, 32 is a sawtooth wave generating circuit, 33 is an operational amplifier, 34 is a transistor, and 35 is a motor. The output duty of the operational amplifier 33 is reduced by increasing the D / A output of the CPU 31. Further, as the ON time of the transistor 34 becomes shorter, the drive torque of the motor 35 decreases.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS.

FIG. 4 is a flow chart of the second embodiment, and FIG. 5 is an explanatory diagram of changes in deterioration on the left side and the right side of the photosensitive drum due to an increase in the number of prints. FIG. 6 is the second
FIG. 7 is a block diagram of the embodiment of FIG. 7, and FIG. 7 is an explanatory diagram of a point-symmetrical image.

Degradation of the photosensitive drum occurs as the number of prints increases, and when viewed from the left side and the right side of the drum, FIG. 5 shows that the left side is severely degraded. Therefore, as shown in FIG. 5, when a certain number of prints is reached, a point-symmetrical image is output, that is, a computer such as a host computer or a word processor is displayed on a screen using an image forming apparatus such as a laser beam printer or a laser beam FAX. When the image is output, the upper left side of the screen is printed on the photosensitive drum from the lower right side, so that it is possible to prevent deterioration of one side of the photosensitive drum.

A means for outputting a point-symmetrical image will be described with reference to FIG.

In FIG. 6, the printer controller unit 6
0 is 61 CPU, 62 RAM, 63 ROM, 64
I / O of 65 and I / O of 65.

As a result of communicating with the printer, the engine reads the number of prints from the EEPROM of the cartridge, and if the result is a fixed number (for example, 1000), the controller section 60 receives from the engine as a status. As a result, the controller section 60 writes data from the final address of the DRAM 8 in the RAM 62 in order to print the image in point symmetry. Next, when all the images have been developed, the image is sent from the ADR0 of the DRAM 1 as usual. That is, as shown in FIG. 7, the data at the lower right end of the page is read first and the data at the upper left end of the page is read last. Therefore, the image becomes point symmetric as compared with the normal time. Change the point symmetry of the image twice (for example, 1
(000 sheets and 2000 sheets) can also be performed.

(Third Embodiment) In a normal electrophotographic process, the high voltage applied to the photosensitive drum in the cartridge from the LBP main body is the primary AC charging output, the primary DC charging output, the developing AC output, the developing DC. Output, transfer charging voltage.

FIG. 8 is an explanatory view of the above-mentioned high voltage related portion. During printing, the primary charging is applied by the charging roller 81 to smooth the potential on the photosensitive drum. The development output is applied by the developing device 83 and embodies the latent image formed by the laser beam 82. When a toner image is formed in the toner container portion 84, a positive transfer charging voltage is output, and the transfer roller 85 transfers the toner image to a sheet.

At the end of printing, after the door is closed, after jamming, etc., a negative transfer charging voltage and a primary AC charging voltage are applied to clean the cartridge, unlike during printing.

Applying only the primary AC charging voltage generally lowers the sensitivity of the photosensitive drum and tends to thin the printed sample. Therefore, repeating one print causes deterioration of the drum rather than continuous multiple printing. for that reason,
A large amount of toner remained on the photosensitive drum, and the printed sample sometimes became thin. In this embodiment, in order to prevent such a phenomenon, the number of times of cleaning of the cartridge is stored in the EEPROM incorporated in the cartridge, and if it is more than the predetermined number, it is judged that the drum has deteriorated and the developing DC voltage The output is set high to correct the low density.

FIG. 9 is a flow chart of the third embodiment, and FIG. 10 is a block diagram showing the main construction of this embodiment.

In FIG. 9, the standby state (S21)
Then, door open / close (S22) or print signal reception (S23) is monitored. When the print signal is received, the total number of cleanings is loaded from the EEPROM in the CRG (S24), and whether it is 2000 or more (S2).
5) Determine whether it is 1000 or more (S26). 2000
If it is above, the development DC output is increased by 10% (S3
2) If it is 1000 or more, the development DC output is increased by 5%.
(S33), and printing is executed (S27). Development DC
The means for changing the output will be described later. After that, the printing operation is maintained and the completion of printing is monitored (S28).

When the printing is completed, the photosensitive drum is cleaned (S29), the total number of cleaning times already loaded is incremented by 1, and the result is written in the EEPROM (S3).
0), return to standby.

When the closing of the door is detected by the standby (S22), the total cleaning number is loaded from the EEPROM in the CRG (S31), the photosensitive drum is cleaned (S29), and the total cleaning number already loaded is detected. +1 is written to the EEPROM (S30), and the operation returns to the standby.

The means for changing the developing DC output will be described with reference to FIG.

In FIG. 10, 100 is a CPU, 101
Is a low-pass filter, 102 is a DC component cutting capacitor, 106 is a transformer, 103 is a comparator, 10
Reference numeral 4 is a reference voltage generating circuit, and 105 is a developing sleeve.

In FIG. 10, the CPU 100 outputs a pulse of a predetermined frequency, and the low-pass filter 10
1, passing through the capacitor 102, becomes a sine wave immediately before the transformer 106, and is boosted by the transformer 106 to generate a developing AC output.

Further, the CPU 100 outputs a development DC output control signal from the D / A port and inputs it to the comparator. The development DC output is generated from the reference voltage generation circuit by the development DC output control signal and added to the development AC output to become a regular development output.

The development DC output control signal generally controls the shade of the print sample according to the user's preference. At the same time, by controlling this signal, the correction signal when the deterioration of the photosensitive drum described above is detected. Use as.

The above configuration and control contribute to stabilizing the quality of the print sample.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIGS. 11 and 12. In the previous embodiment, the DC output for development was changed when the deterioration of the drum was sensed. In the present embodiment, instead of this, the light quantity of the laser is changed.

In the flowchart shown in FIG. 11, the same steps as those in the flowchart of FIG. 9 of the third embodiment are indicated by the same step numbers, and only the portions different from the previous embodiment will be described. In S25 and S26, it is monitored whether the value is 2000 or more and 1000 or more, and if 2000 or more, the laser light amount is 20% UP (S42), and if it is 1000 or more, the laser light amount is 10% UP (S43).

FIG. 12 is a block diagram showing a specific configuration of the laser light amount UP.

Reference numeral 120 is a CPU, 121 is a laser driving circuit, 122 is a laser, 123 is a light quantity measuring pin photodiode, 124 is an amplifier, and 125 is a comparator.

The CPU 120 uses the D / A port 126 to determine the laser light amount reference. The value is compared with the measurement result of the light quantity measuring pin photodiode 123 by the comparator 125, and the result is reflected in the laser drive circuit 121. Therefore, by changing the D / A port 126, a light amount of 10% UP and 20% UP can be realized.

Therefore, a stable print sample can be realized by changing the laser light amount according to the deterioration of the drum due to repeated cleaning.

[0053]

As described above, according to the present invention,
It is possible to prevent the deterioration of the photosensitive drum caused by repeating printing with the same cartridge. Further, the extension of the life of the photosensitive drum makes it possible to prevent deterioration of the image quality of the print sample. It goes without saying that image distortion will disappear over the long term as long as the same cartridge is used.

[Brief description of drawings]

FIG. 1 is a flowchart of a first embodiment.

FIG. 2 is a drive torque explanatory diagram of the first embodiment.

FIG. 3 is a block diagram of a main part of the first embodiment.

FIG. 4 is a flowchart of a second embodiment.

FIG. 5 is an explanatory diagram of a change in deterioration of the photosensitive drum of the second embodiment.

FIG. 6 is a block diagram of an essential part of a second embodiment.

FIG. 7 is an explanatory diagram of a point symmetric image according to the second embodiment.

FIG. 8 is an explanatory diagram of a high voltage related portion of the third embodiment.

FIG. 9 is a flowchart of a third embodiment.

FIG. 10 is a principal block diagram of a third embodiment.

FIG. 11 is a flowchart of a fourth embodiment.

FIG. 12 is a block diagram of main parts of a fourth embodiment.

FIG. 13 is a cross-sectional explanatory diagram of a conventional laser beam printer.

FIG. 14 is a drive torque explanatory diagram of a conventional example.

[Explanation of symbols]

1 Laser beam printer 2 photosensitive drum 3 Scanner unit 5 charger 6 developer 7 Transfer roller 8 drum cleaner

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tetsuo Saito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-5-80651 (JP, A) JP-A-6 -138765 (JP, A) JP-A-4-330471 (JP, A) JP-A-7-175370 (JP, A) JP-A-4-267276 (JP, A) JP-A-63-299938 (JP, A) ) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/00 303 G03G 21/00 370-540 G03G 21/14-21/18 G03G 15/08-15/08 507 G03G 15/00 550 H04N 1/23-1/31

Claims (2)

(57) [Claims] 1. A incorporating a photosensitive body and non-volatile memory
An image forming apparatus for forming an image on a recording medium equipped with cartridges, the number of printed sheets obtained by using the previous asked cartridges have a read-write means for writing the read or the non-volatile memory from the non-volatile memory, said non volatile memory The image to be formed is switched to point symmetry according to the lead from
An image forming apparatus, comprising: 2. The non-volatile memory is an EEPROM.
The image forming apparatus according to claim 1, wherein: