JP2001092194A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which detects a sensitivity characteristic and new and old states as well in addition to the eccentricity (phase) of a photoreceptor drum with simple constitution. SOLUTION: A reflection plate 77 of a semicircular shape is mounted at an irregular gear wheel 78 having a gear only at its half circumference and the end of the gear of this irregular gear wheel 78 is meshed with a drum gear 81 of a photoreceptor drum 79 and is so initially set that the end of the reflection plate 77 intrudes into the detecting optical path of a drum sensor 75. When the photoreceptor drum rotates at fresh operation, the irregular gear wheel 78 rotates half and stops by disengaging from the meshing. During this time, the drum sensor 75 detects the reflection plate 77 and recognizes that the photoreceptor drum is a brand new product. A phase mark 82 is thereafter detected at specified intervals. When the area of the sectorial shape of the phase mark is changed according to the previously measured sensitivity of the photoreceptor drum, the sensitivity of the photoreceptor drum may be easily detected on the main body side of the image forming device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus which has a simple structure and detects the eccentricity of a photosensitive drum and the sensitivity characteristics of the photosensitive drum and the new and old states of the photosensitive drum.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus for forming an image on a paper using toner has been used. FIG. 12 (a)
FIG. 2 is a side sectional view schematically showing a configuration of a main part of such an image forming apparatus. FIG. 2B is a perspective view of the photosensitive drum, and FIG. FIG. 5 is a diagram showing an operation state of FIG.

As shown in FIG. 1A, a main part of the image forming apparatus is formed along a peripheral surface of a photosensitive drum 2 which is supported by a support shaft 1 and rotates clockwise as indicated by an arrow A in the figure. A charger 3, an optical writing head 4, a toner kit 5, and a developing roller 6 rotatably supported on a lower side surface of the toner kit 5.
And a sheet P in contact with the lower peripheral surface of the photosensitive drum 2.
Is transported to the left as shown by the arrow B in the figure.

In this image forming apparatus, the charger 3 applies a high charge to the peripheral surface of the rotating photosensitive drum 2 to uniformly initialize the peripheral surface, and the optical writing head 4 applies image information to the initialized peripheral surface. To form an electrostatic latent image composed of a high-potential part by initialization and a low-potential part whose potential has been attenuated by exposure, and the developing roller 6 removes the toner in the toner kit 5 The photosensitive drum 2 rotates and conveys the visualized toner image, and a transfer unit (not shown) sequentially transfers the rotationally conveyed toner image onto the paper P. The toner image formed on the paper P is fixed by a fixing device (not shown).

[0005] In such an image forming apparatus, a driven portion such as the photosensitive drum 2 receives a driving force from a motor via a drive transmission system including a gear train. In order to engage with the terminal gear of this driving force transmission system, the photosensitive drum 2
Has a gear 7 at the end as shown in FIGS.

In general, there is a limit in the manufacturing accuracy of any member. Therefore, the above-mentioned photosensitive drum is also eccentric, and a gear train of a drive transmission system for rotating the photosensitive drum is also required. Rotational unevenness due to gear eccentricity occurs. Such rotation unevenness is unavoidable,
Normally, after unavoidable rotation unevenness is allowed, an optical writing head is synchronized with the above-described unevenness phase in order to normally form an image transferred from the photosensitive drum having the rotation unevenness to the paper surface. 4 controls the timing of exposure.

In this case, in order to control the exposure timing by detecting the phase of the unevenness at an initial stage, as shown in FIG. 1B, the eccentricity of the photosensitive drum 2 is set on the side surface of the gear 7 of the photosensitive drum 2. The mark 8 is applied to the corresponding position, and the mark 8
Is read by the optical sensor 9 to detect the phase of the unevenness, as shown in FIG.

Incidentally, the image forming apparatus is not limited to an image forming apparatus having a single exposure, development, and transfer unit to perform monochrome printing as described above, and recently an image forming apparatus performing full-color printing. Has been widely put to practical use.

FIG. 13 is a side sectional view schematically showing the internal structure of such a full-color image forming apparatus, with the drive transmission system not shown. A full-color image forming apparatus (hereinafter simply referred to as a color printer or a main unit) 1 shown in FIG.
No. 0 has an openable / closable paper feed tray 12a on the front (right side in the figure) and an openable / closeable paper discharge tray 12b on the back side (left side in the figure). At an upper front end, an operation panel 11 on which a power switch (not shown), a liquid crystal display device, a plurality of input keys, and the like are arranged is provided.

An upper cover 14 is provided on the upper surface of the main unit 10,
The rear part of the upper lid 14 forms an upper paper discharge tray 15 together with the rear upper surface of the main body device 10. In addition, a paper cassette 13 which is detachable from the front is provided at a lower portion of the main body device 10,
A large number of sheets are placed and stored on a bottom plate 13-1 of the sheet cassette 13 which is urged upward by an urging member (not shown).

A paper transport belt (hereinafter simply referred to as a belt) 16 is disposed substantially in the center of the main unit 10 in a front and rear flat loop shape.
And is circulated in the counterclockwise direction indicated by arrow C in the figure. 4 in the upper circulation part of the belt 16
Photoconductor drums 19 (19a, 19b, 19c, 19)
d) are arranged in a multi-stage manner in the paper transport direction (from right to left in the figure), and surround each of the photosensitive drums 19 (hereinafter, only the reference numerals for the peripheral devices of the photosensitive drum 19d are representatively shown). , A cleaner 21, an initialization charging brush 22, an optical writing head 23, a developing unit 24, and a transfer brush 25.

The optical writing head 23 includes a support member 2
6 is provided on the back surface of the upper lid 14 via the upper lid 14.
Is lowered in accordance with the closing of the photosensitive drum 19, and is positioned so as to face the photosensitive drum 19, where a recording portion by optical writing is formed.

Developing device 24 corresponding to photosensitive drum 19a
, To magenta (M), cyan (C), yellow (Y), and black (Bk) toners 27, respectively. A developing roller 28 is rotatably supported at the lower opening of each developing device 24.
Abuts on the peripheral surface of the photosensitive drum 19 to form a developing section there.

The transfer brush 25 is pressed against the photosensitive drum 19 via the belt 16 to form a transfer portion.

The belt 16 is constantly urged downward by a tension roller 29 which presses against the lower surface of the downstream side of the lower circulating section to maintain an appropriate tension. The suction roller 31 is pressed against the upstream end of the upper circulating portion of the belt 16 to form a paper carry-in portion.

On the upstream side (right side in the drawing) of the belt 16 in the transport direction, a pair of standby rolls 32 is provided.
3. A feed roll pair 34 is provided at the lower end. A paper feed end of the paper cassette 13 is located below the feed roll pair 34, and a paper feed roller 35 is disposed above the paper feed end. On the other hand, on the downstream side of the belt 16 in the paper transport direction (left side in the figure), a pressing roller, a heating roller, a separating claw, a peripheral cleaning device, an oil application roller, a temperature measuring device, and the like are installed. Is provided.

A discharge guide path 37 is formed downstream of the fixing device 36 with the open / close discharge tray 12b closed, and a discharge roll pair 38 is disposed at the end of the discharge guide path 37. . Further, an electrical unit 39 provided with an appropriate circuit board is disposed between the belt 16 and the paper cassette 13, and a control device including a plurality of electronic components is mounted on the circuit board.

When the power of the color printer 10 is turned on, and the paper quality, the number of sheets to be used, the print mode, and other designations are input as a key input or a signal from a connected host device, printing (printing) is performed. Start. First,
The feed roller 35 takes out one sheet of the uppermost sheet stored in the sheet cassette 13 every rotation and feeds a pair of feed rollers 34.
And the feed roll pair 34 feeds the paper to the standby roll pair 32. The standby roll pair 32 temporarily stops the rotation, stops the advance of the sheet, and waits for the transport timing.

Subsequently, the driving roller 17 and the driven roller 18
Rotates counterclockwise to start the circulating movement of the belt 16. The developing device 24 and the photosensitive drum 19 are also sequentially driven according to the printing timing, and the photosensitive drum 19 rotates clockwise.

The initialization charging brush 22 is used for the photosensitive drum 1
A uniform high negative charge is applied to the 9 peripheral surfaces, and the optical writing head 23 exposes the peripheral surface of the photosensitive drum 19 in accordance with the image signal, and a high negative potential portion by the above initialization and the above exposure. An electrostatic latent image composed of a low negative potential portion is formed. The developing roller 28 of the developing device 24 transfers the toner 27 to the low potential portion of the electrostatic latent image and
A toner image is formed on the peripheral surface (reversal development).

When the leading end of the toner image on the peripheral surface of the photosensitive drum 19a at the most upstream position is rotated and conveyed to the portion facing the belt 16, the printing start position of the paper coincides with the facing portion. The standby roll pair 32 starts rotating and feeds the sheet to the sheet carry-in section. The attraction roller 31 presses the belt 16 while applying an attraction bias supplied from a bias power supply (not shown) to the belt 16 to electrostatically attract the paper to the belt 16. The sheet is attracted to the belt 16 and is conveyed to the first transfer section formed by the photosensitive drum 19a and the transfer brush 25.

The transfer brush 25 applies a transfer current output from a transfer bias power supply (not shown) to the sheet via the belt 16 to transfer the magenta (M) toner image on the photosensitive drum 19a to the sheet. . Subsequently, the photosensitive drum 19
b and the second transfer portion by the transfer brush 25 transfers the cyan (C) toner image, and the third transfer portion by the photosensitive drum 19c and the transfer brush 25 transfers the yellow (Y).
And the lowermost transfer portion by the photosensitive drum 19d and the transfer brush 25 is black (Bk).
Is transferred.

The paper on which the toner images of the four colors are superimposed and transferred is separated from the belt 16 and carried into a fixing device 36. The fixing device 36 fixes the toner image on the paper by applying heat and pressure to the paper. Discharge backward. When the open / close sheet discharge tray 12b is opened rearward, the sheet is opened and closed.
2b is discharged with the toner image facing up. Also, when the open / close discharge tray 12b is rotated rightward and is closed as shown in the figure, a discharge guide path 27 formed by the open / close discharge tray 12b and a discharge roll pair 28 at the end thereof. And is discharged onto the upper discharge tray 15 with the toner image downward.

FIG. 14 is a side view showing the configuration of the drive transmission system in the color printer 10. The above-described drive roller 17 and photosensitive drums 19a, 19b, 19c, 19
d, standby roll pair 32, feed roll pair 34, paper feed roller 3
5, and the rotating portion of the fixing device 36 are driven to rotate by engaging with a drive system including a gear train shown in FIG. The developing roller 28 engages with the drum gear of the photosensitive drum 19 and is driven indirectly with the above-mentioned gear train, and the paper discharge roll pair 38 engages with the fixing device 36 to form the same gear train. Driven indirectly.

As shown in FIG.
9 (19a, 19b, 19c, 19d) has a drum gear 41 (41a, 41b, 41c, 41
d) is provided integrally with the photosensitive drum 19 (not shown in FIG. 14). And those drum gears 41
And the drum drive gears A1, A2, A3 and A4 are in mesh with each other. Further, these drum driving gears A1, A
Reduction gears B1, B2, B3, and B4, in which a large-diameter gear and a small-diameter gear are integrally formed, mesh with 2, A3, and A4, respectively.

The large-diameter gear of the reduction gear B1 meshes with the small-diameter gear of the drive-side reduction gear C1.
One reduction gear C2 on the driving side is attached to the large-diameter gears 2 and B3.
Are geared with each other. And these reduction gears C
The large diameter gears 1 and C2 mesh with one clutch gear 42. The clutch gear 42 meshes with a drive shaft gear of a drum drive motor 46 via a reduction gear 43 and idle gears 44 and 45.

The above-mentioned drum gears 41a, 41b, 41c
And 41d are gears of the same shape formed by the same mold, and are drum driving gears A1, A2, A3 and A4.
Are gears of the same shape formed by the same mold.
Further, the reduction gears B1, B2, B3 and B4 are gears of the same shape formed by the same mold. Further, the reduction gears C1 and C2 are gears having the same shape. Therefore,
The driving force transmitted from the drum drive motor 46 to the clutch gear 42 via the idle gears 45 and 44 and the reduction gear 43 has the same rotational characteristics transmitted downstream via the reduction gears C1 and C2. C1 through a reduction gear B1 and a drum drive gear A1 to the photosensitive drum 19
a and the photosensitive drum 19b from the reduction gear C2 via the reduction gear B2 and the drum drive gear A2.
And the rotation characteristics transmitted from the reduction gear C2 to the photosensitive drum 19c via the reduction gear B3 and the drum drive gear A3 are also the same.

A reduction gear C is provided between the reduction gear B4 corresponding to the photosensitive drum 19d and the drum drive motor 46.
And the large-diameter gear is the drum drive motor 4
6 and the small-diameter gear meshes with the large-diameter gear of the reduction gear B4. In this drive system, the reduction gear C4
The rotation characteristics transmitted to the photosensitive drum 19d via the reduction gear B4 and the drum drive gear A4 from the reduction gear C1 or the reduction gear C2 described above change the rotation characteristics.
The gear ratio between the idle gears 45, 44, and 43 is set so as to be the same as the rotation characteristic transmitted to the gear b or 19c.

Although not shown, the idle gear 44 includes a plurality of reduction gears, an idle gear, and a clutch. (Not shown) are engaged and driven to rotate.

Although not shown, a belt drive motor is provided separately from the drum drive motor 46. The belt drive motor is connected to a drive shaft gear, an idle gear, and a reduction gear (not shown). Thus, the gear of the driving roller 17 for driving the paper transport belt 16 and the gear of the heat generating roller of the fixing device 36 are driven to rotate.

In this configuration, the drum driving motor 46
Drum 19 that is performed through the above-described gear train
As described above, the gears at the same position in the gear train are formed in the same shape using the same mold as described above, and the gear ratio of these gear trains and Based on the positional relationship of the drum 19, the photosensitive drum 19 is assembled so that the rotation characteristics of the photosensitive drum 19 at the image transfer position match.

The drive system for the photosensitive drums 19a to 19c is divided into a drive system for the photosensitive drums 19a to 19c and a drive system for the photosensitive drum 19d.
In monochrome printing, driving is stopped. When the monochrome printing is completed, a position shift of the rotation characteristic occurs between the photosensitive drum 19d driven during the monochrome printing and the other three photosensitive drums 19a to 19c stopped during the printing.

Therefore, when the power is turned on when the use of the main unit 10 is resumed, it is unclear whether the previous use state was a monochrome print or a color print, and it is assumed that the use was a monochrome print. Then, it is necessary to adjust again the above-mentioned positional deviation, which should have occurred in that case, again in synchronization with the case of performing color printing.

To this end, a mark is provided at a predetermined position on the drum driving gear A3, and a mark is also provided at a predetermined position on the drum driving gear A4. And FIG.
As shown in FIG. 3, sensors 47 and 48 for detecting the marks on the drum driving gears A3 and A4 are provided in the main assembly 1 of the apparatus.
0 is fixed to a frame (not shown). The positional relationship between these sensors 47 and 48 and the marks on the drum driving gear A3 and the marks on the drum driving gear A4 is such that the photosensitive drum 19d is at the reference position when the sensor 48 detects the mark on the drum driving gear A4. Is set so that the photosensitive drum 19c is at the reference position when the sensor 47 detects the mark of the drum driving gear A3.

Then, as described above, the photosensitive drum 1
If 9c is at the reference position, the photosensitive drums 19b and 19c
a is also assembled so as to be at the reference position. Therefore, if the synchronization of the drum driving gears A3 and A4 (synchronization of the phase of the rotation characteristics, the same applies hereinafter), the synchronization of the four drum driving gears 41a to 41d can be naturally obtained.

By the way, the unevenness of the rotation characteristics requiring the above-described alignment occurs not only in the gear train of the drive system but also in the photosensitive drum and the drum gear. Of course, at the time of assembly at the factory, the drum gear of the photosensitive drum and the drum drive gear are assembled in synchronization with each other, so that the photosensitive drums 19a to 19a to 1 in the same drive system are used.
There is no rotation phase shift between 9c. However, the drum drive gear (A3 or A4) and the drum gear (41c or 4)
Since the number of teeth in 1d) is different, even if the drum driving gears A3 and A4 are synchronized as described above after driving only the photosensitive drum 19d in monochrome printing, the drum gear 41c
And 41d are not always at the reference position.

Of course, if the photosensitive drum and the drum gear are made with extremely high precision, there will be no difference in the rotational phase. Therefore, it is only necessary to synchronize the drum driving gears A3 and A4 as described above. In addition, in order to produce the drum gear with high precision, it is necessary to solve the problem that the manufacturing cost is significantly increased. If the unevenness of the rotation characteristics of the photosensitive drum, that is, the drum gear can be absorbed, the accuracy of the drum gear may be made with the same accuracy as that of the gears of the other drive trains described above. Can be suppressed.

The sensors 49 and 51 shown in FIG. 14 are arranged to absorb unevenness in the rotation characteristics of the drum gear, and are provided on the side surface of the gear 41c of the photosensitive drum 19c and the side surface of the gear 41d of the photosensitive drum 19d. It is provided for reading a mark, which will be described later, attached to each.

FIG. 15A shows the photosensitive drum (19c).
Or 19d) a mark on the gear side and a sensor (49 or 5)
FIG. 2 is a partially exploded perspective view showing the configuration of 1), and FIG.
(b) is a figure which expands and shows a part.

In FIG. 15A, the image forming unit 5
2 includes a developing unit 53 including a developing device 24 and the like that stores the toner 27 shown in FIG. 13 therein and holds the developing roller 28 at a lower portion, the photosensitive drum 19, the cleaner 21, the initialization charging brush 22, and the like. Drum unit 54 is integrally assembled via a unit frame 55. From a side surface of the unit frame 55, a developing roller shaft 56 and a photosensitive drum shaft 57 project outside. Incidentally, the photosensitive drum 19 (19c, 19d) shown in FIG.
7 is omitted. The same applies to FIG.

The image forming unit 52 includes the main unit 1
When mounted on the unit receiving portions 58a and 58b, one end of the developing roller shaft 56 and the photosensitive drum shaft 57 (the end in the obliquely upward direction in the drawing) is a bearing 58a- of the unit receiving portion 58a. 1 and 58a-2, and the other end (the end in the obliquely forward direction in the figure) is the unit receiving portion 58b.
Is also fixed to the bearing portion (not shown in the figure in the shade). The photosensitive drum 19 is supported by the fixed photosensitive drum shaft 57 and driven by the drive system of the main body device 10 via the drum gear 41. The developing roller 28 is supported by the fixed developing roller shaft 56. , A roller gear (not shown) is driven by engaging with the drum gear 41.

At a predetermined position on the gear side surface 59 of the photosensitive drum 19c (and 19d), a fan-shaped mark 61 of an appropriate size is formed. On the other hand, the image forming unit 52
On the side wall of the drum unit 54 facing the gear side surface 59, the mark 61 is provided with the photosensitive drum 19c (or 1).
When it comes to the reference position with the rotation of 9d), a detection hole 62 is formed at a position corresponding to the reference position. Also, on the side wall of the unit frame 55 facing the detection hole 62,
A detection hole 63 is provided. A detection hole 64 is formed in a wall surface of the unit receiving portion 58b of the main body device 10 facing the detection hole 63.

A sensor 49 (or 51) is provided inside the unit receiving portion 58b corresponding to the detection hole 64. The sensor 49 (or 51) is a reflection type photo sensor,
As shown in FIG. 3B, the light emitting portion radiates the irradiation light 65a from the light emitting portion to the rotating surface of the gear side surface 59 through the detection holes 64, 63, and 62, and receives the reflected light 65b at the light receiving portion. When the mark 61 comes to a position facing the mark 62, the mark 61 is detected.

By the way, even if the structure of the gear train of the drive system and the manner of transmission of the drive are carefully noted, the photosensitive characteristics of the photosensitive drum to be driven vary in the photosensitive characteristics depending on the manufacturing lot. For this reason, the electrostatic latent image formed on the peripheral surface, that is, the toner image visualized thereon, that is, the density of the printed image transferred and fixed on the paper surface varies.

Such variations in the photosensitive characteristics of the photosensitive drums affect the output image. In particular, in the case of a full-color image, if the photosensitive characteristics of the three photosensitive drums for color differ as described above, The color difference is increased and the image quality is significantly reduced.

Therefore, even if the problem caused by the rotation unevenness due to the eccentricity of the drive system and the photosensitive drum itself is eliminated as described above, good image quality can be obtained if the photosensitive characteristic unevenness of the photosensitive drum is left as it is. I can't keep it.

In order to prevent the image quality from being degraded due to the unevenness of the photosensitive characteristics of the photosensitive drum, the surface potential of the photosensitive drum is measured in a printer device, or a color is called a patch on a belt. The density of the printed image is examined by a method of printing out the density sample as a test and measuring the density, and a maintenance worker such as a serviceman adjusts the sensitivity of each photosensitive drum.

In general, in the above-mentioned electrophotographic printer using toner, detection of the presence or absence of consumables such as toner of a photosensitive drum and a developing device, detection of old and new of these consumables, and Detecting the rotational phase of the photosensitive drum is performed as an almost essential matter.
Then, for these detections, a method is employed in which detection is performed by dedicated detection sensors.

[0049]

However, in a conventional electrophotographic printer, the method of measuring the potential of the surface of the photosensitive drum inside the printer requires a large-sized main unit and a recent market for miniaturization of OA equipment. In addition to the demand, there is a problem that the price of the main unit increases.

Further, the method of outputting a patch on a belt and measuring the density thereof is liable to be affected by the accuracy of the sensor when measuring the color toner, and the adjustment must be performed. there were.

Further, there is a method of adding the sensitivity information of the photosensitive drum to the drum unit. However, it is necessary to provide a dedicated sensor for reading the sensitivity information, which increases the number of parts and increases the number of parts. However, there is still a problem in that it is difficult to reduce the size by high-density mounting, which is a factor that hinders cost reduction.

The object of the present invention is to solve the above-mentioned conventional problems.
It is an object of the present invention to provide an image forming apparatus which has a simple configuration and detects not only the eccentricity (phase) of the photosensitive drum but also the sensitivity characteristics of the photosensitive drum and the new and old states of the photosensitive drum.

[0053]

According to the first aspect of the present invention, there is provided an image forming apparatus comprising: a photosensitive drum exchangeably disposed on an apparatus main body; a charging unit for charging a surface of the photosensitive drum; An optical unit that irradiates a light signal corresponding to image information to the surface of the photosensitive drum charged by the charging unit to form an electrostatic latent image; and the static unit formed on the surface of the photosensitive drum by the optical unit. A toner image forming means for visualizing the electrostatic latent image into a toner image, a transfer means for transferring the toner image visualized by the toner image forming means onto a transfer material to be conveyed, and a photosensitive drum An image forming apparatus comprising at least a rotation phase information notifying unit for notifying rotation phase information, and a control unit for controlling timing of light signal irradiation by the optical unit based on information from the rotation phase information notifying unit, ,Up Rotation phase information notifying unit detects the information corresponding to the sensitivity characteristics of the photosensitive drum information and the photosensitive drum corresponding to the eccentricity of the information 1
And the amount of light by the charging unit or the amount of light irradiation by the optical unit based on predetermined image information is corrected according to the sensitivity characteristic of the photosensitive drum detected by the detecting unit. The apparatus is provided with a process condition control means for controlling the set value.

Next, an image forming apparatus according to a second aspect of the present invention includes a photosensitive drum exchangeably disposed on an apparatus main body;
Charging means for charging the surface of the photosensitive drum, optical means for irradiating a light signal corresponding to image information to the surface of the photosensitive drum charged by the charging means to form an electrostatic latent image, and the optical means A toner image forming means for visualizing the electrostatic latent image formed on the surface of the photosensitive drum into a toner image, and a transfer material on which the toner image visualized by the toner image forming means is conveyed. Transfer means for transferring the rotation phase information to the photosensitive drum, rotation phase information notifying means for notifying the rotation phase information of the photosensitive drum, and control for controlling the timing of light signal irradiation by the optical means based on the information from the rotation phase information notification means. Means for notifying the rotational phase information, the information corresponding to the eccentricity of the photosensitive drum and the information corresponding to the old and new states of the photosensitive drum. It constituted a single detection means for detecting et information.

Further, in the image forming apparatus according to the third aspect of the present invention, there is provided an image forming apparatus comprising:
Charging means for charging the surface of the photosensitive drum, optical means for irradiating a light signal corresponding to image information to the surface of the photosensitive drum charged by the charging means to form an electrostatic latent image, and the optical means A toner image forming means for visualizing the electrostatic latent image formed on the surface of the photosensitive drum into a toner image, and a transfer material on which the toner image visualized by the toner image forming means is conveyed. Transfer means for transferring the rotation phase information to the photosensitive drum, rotation phase information notifying means for notifying the rotation phase information of the photosensitive drum, and control for controlling the timing of light signal irradiation by the optical means based on the information from the rotation phase information notification means. Means for notifying the rotational phase information, the information corresponding to the eccentricity of the photosensitive drum, the information corresponding to the sensitivity characteristic of the photosensitive drum, and And information corresponding to the old and new state of the light drum, constituted by a single detection means for detecting the information.

[0056]

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

FIG. 1 is a block diagram showing the configuration of the image forming apparatus according to the first embodiment. The basic configuration of the details of this image forming apparatus is substantially the same as the configuration of the image forming apparatus 10 shown in FIG. 13 except for the configuration described in detail in FIG. Figure 1 accordingly
The names and numbers of the components of the image forming apparatus 10 shown in FIG.

As shown in FIG. 1, the image forming apparatus 70
An MPU 71, which is a central control unit, includes a driving unit 72, a head driver unit 73, a drum sensor 75, and an EEPROM 76 connected to the MPU 71. An optical writing head 74 is connected to the head driver unit 73. The MPU 71, the driving unit 72, the head driver unit 73, and the EEPROM 76 are mounted on the circuit board of the electrical unit 39 in FIG.

The drive section 72 drives the drum drive motor 46 for driving the gear train described with reference to FIG. 14 under the control of the MPU 71, and the belt drive motor and clutch not shown in FIG.

The optical writing head 74 has the same configuration as that of the optical writing head 23 shown in FIG. 13. The optical writing head 74 is composed of a fine pitch LED array. The head driver unit 73 controls the LED of the optical writing head 74 according to the image data under the control of the MPU 71.
The element is selectively driven to emit light. The drum sensor 75 will be described later in detail with reference to FIG.
Detect street conditions. The EEPROM 76 stores various preset reference values, detection data detected by sensors, and the like.

FIG. 2A is a view showing the shape of a rotary reflector disposed in conjunction with the photosensitive drum of the image forming apparatus, and FIG. 2B is a view showing the shape of the rotary gear. Figure showing, same figure
(c) is a perspective view showing the initial operation state, FIG.
It is a side view showing the middle operation state.

FIG. 3A is a perspective view showing a late operation state following the above-mentioned middle operation state, and FIG. 3B is a side view showing the final operation state.

In general, magenta (M), cyan (C),
Four FIG. 15 of yellow (Y) and black (Bk)
As shown in FIG. 13, in a so-called tandem type printer in which the image forming units 52 shown in FIG. 13 are arranged in multiple stages along the paper transport direction, first, FIG. 12 (b) and FIG. 15 (b) As described above, in order to represent the phases of the photoconductor drum 19d for Bk printing and the photoconductor drums 19a, 19b and 19c for M, C and Y color printing, a phase mark is provided on the gear side surface of the photoconductor drum. (Reflection marks), the reflection marks are detected by a reflection type optical sensor, and all the photosensitive drums are aligned.

In the present invention, not only a phase mark is simply detected, but also a new or old photosensitive drum is detected by using a sensor for detecting the phase mark. That is, in this embodiment, as shown in FIG. 2A, a semicircular reflector 77 is prepared, and
7 is attached to the rotating shaft 78-1 of the irregular gear wheel 78 as shown in FIG. The irregular gear wheel 78 is provided with a gear 78-2 only on a half circumference and without a gear on the other half circumference, and has a semicircular straight portion (diameter) of the reflector 77 and an irregular gear wheel 78. Is shifted from the gear 78-2 by a predetermined angle θ.

When the image forming unit of this embodiment is in a new state, the drum gear 81 of the photosensitive drum 79 is displaced from the drum gear 81 of the photosensitive drum 79 by the angle θ of the gear 78-1 of the irregular gear wheel 78, as shown in FIG. The ends located inside (the position hidden behind the back surface) of the reflection plate 77 are arranged so as to mesh with each other.

In this state, the lower part of the side surface 81-1 of the drum gear 81 of the photosensitive drum 79 is provided with the gear 78 of the irregular gear wheel 78 of the reflection plate 77 meshing with the drum gear 81.
-2 is covered by an end that is shifted outward by an angle θ (a part preceding in the counterclockwise direction) from the end of −2.

A phase mark 82 is provided on a side surface 81-1 of the drum gear 81, and a drum sensor 75 is arranged to scan a lower surface of the side surface 81-1 of the drum gear 81. When the image forming unit is in a new state, the lower surface of the side surface 81-1 of the drum gear 81 is covered by the reflection plate 77 as described above.
As shown in (c), the reflected light from the reflector 77 is always detected.

When this new image forming unit is mounted on the image forming apparatus and an instruction to start printing is issued, first, the photosensitive drum 79 rotates clockwise as shown by arrow E in the figure. Thus, the irregular gear wheel 78 meshing with the drum gear 81 rotates in the counterclockwise direction indicated by the arrow F in the figure. In this initial operation state, the drum sensor 75
Detects the reflected light from the end of the reflection plate 77.

Subsequently, as the photosensitive drum 79 continues to rotate, the irregular gear wheel 78 follows the rotation of the photosensitive drum 79, and the central portion of the reflection plate 77 is moved to the side 81-1 of the drum gear 81 as shown in FIG. Pass through the lower surface of the. In the middle operation state, the drum sensor 75 still detects the reflected light from the reflecting plate 77 (however, the reflected light at the center).

Further, with the continued rotation of the photosensitive drum 79, the irregular gear wheel 78 follows the rotation, and as shown in FIG. The end shifted inward is the drum gear 81.
Pass through the lower surface of the side surface 81-1. In this late operation state, the scanning optical path of the drum sensor 75 to the side surface 81-1 of the drum gear 81 is opened.

Then, as the photosensitive drum 79 continues to rotate, the gear 78 of the irregular gear wheel 78 is driven by the rotation.
-2 is disengaged from the engagement with the drum gear 81, and as shown in FIG.
Stops while supporting the reflecting plate 77 downward. Due to this final operation state, the scanning optical path of the drum sensor 75 to the side surface 81-1 of the drum gear 81 remains open until a new image forming unit is mounted next time. Further, in this state, the phase mark 82 is detected by the drum sensor 75 at a constant cycle as the photosensitive drum 79 rotates.

FIG. 4A is a diagram showing a waveform of a detection signal of the drum sensor 75 when the image forming unit is new, and FIG. 4B is a diagram showing a waveform when the image forming unit is old. FIG. 7 is a diagram showing a waveform of a detection signal of a drum sensor 75.
When the image forming unit is new, as shown in FIG.
Then, the drum sensor 75 is driven, the drum sensor 75 detects the reflected light from the reflection plate 77, and the output is immediately turned on (see FIG. 2 (c)). This detection state is at time T2
2 (d)), and at that time T2, the detection signal is turned off due to the reflection plate 77 deviating from the scanning optical path of the drum sensor 75 (see FIG. 3 (a)).

The MPU 71 compares the detection period of the reflection plate 77 stored in the EEPROM 76 in advance with that of FIG.
It is recognized that the detection signal from time T1 to time T2 shown in FIG. That is, it recognizes that the image forming unit is new.

According to the position of the phase mark 82 at this time,
Next, a time T3 at which the light reflected by the phase mark 82 is detected.
The period up to is irregular, but once the phase mark 82 is detected at the time T3, the time T4 of the constant cycle, and further,
Although not shown in the figure, the phase mark 8
2 is detected.

The MPU 71 compares the detection cycle of the phase mark 82 stored in the EEPROM 76 in advance with the detection cycle of the phase mark 82 from time T3 to time T4 and recognizes that it is the detection cycle of the phase mark 82. The falling of the signal is recognized as the reference position of the rotation phase of the photosensitive drum.

On the other hand, when the image forming unit is an old product, the relationship between the photosensitive drum 79 and the reflecting plate 77 is as shown in FIG.
As shown in FIG. 4B, the reflection plate 77 is always out of the scanning optical path of the drum sensor 75.
As shown in FIG. 7, the rotation start time t1 of the photosensitive drum 79
Thus, even if the drum sensor 75 is driven, the detection output is off because there is no reflector 77.

Also in this case, since the initial position of the phase mark 82 is indefinite, the period until time t2 when the reflected light from the phase mark 82 is first detected is irregular, but once the phase mark 82 is detected at time t2. Is detected, a phase mark 82 is detected at a time t3 of a fixed cycle (t2 to t3 = T3 to T4), and at a time of the same cycle following the time T4 or time t3 in the figure. That is, when the period of the first detected ON signal is long, the image forming unit is new, and when the ON signal is short, it is old. Then, the rotation phase of the photosensitive drum can be detected at the falling edge of the short ON signal detected at a constant cycle.

As described above, one drum sensor 75 can detect both the new and old image forming units (in this case, the photosensitive drum of the image forming unit) and the rotational phase of the photosensitive drum. In the present invention, further,
The sensitivity characteristic of the photosensitive drum can be easily detected by one drum sensor 75. This will be described as a second embodiment.

FIGS. 5A, 5B, and 5C are diagrams showing examples of fan-shaped marks provided on the side surface of the photosensitive drum of the image forming apparatus according to the second embodiment. Note that the basic configuration of the image forming unit in the present embodiment is the same as that in the first embodiment.

FIG. 5A shows a fan-shaped phase / sensitivity mark 83a indicating the rotational phase and the sensitivity characteristic applied to the drum gear side surface 81-1a of the photosensitive drum 79a (hereinafter, simply referred to as the photosensitive drum side surface). FIGS. 8B and 8C show the phase / sensitivity marks 83b and 83 of the photosensitive drums 79b and 79c having different sensitivity characteristics from the photosensitive drum 79a, respectively.
c is shown.

As shown in FIGS. 9A, 9B and 9C, the phase / sensitivity marks 83 on the photosensitive drums 79a, 79b and 79c are provided.
a, 83b, and 83c are 15%, respectively, of the area of the side surface of the photosensitive drum in accordance with the respective sensitivity characteristics described later.
It is provided in a fan shape with an area that gradually increases so as to have a ratio of 30% and 45%.

When these photosensitive drums 79a, 79b or 79c are mounted on the image forming apparatus and rotated in the clockwise direction indicated by the arrow E in the figure, which is the rotation direction of image formation, FIGS. 2 (c) and 2 (d) The phase / sensitivity mark 83a, 83b or 83c is detected by the drum sensor 75 shown in FIGS. 3 (a) and 3 (b).

FIGS. 6 (a), 6 (b) and 6 (c) show that these photosensitive drums 79 (79a, 79b and 79c) are integrated with the irregular gear wheel 78 shown in FIG. 2 (c). It is a figure which shows the waveform of the detection signal by the drum sensor 75 at the time of a brand-new state when it is comprised in combination with 77, (d), (e), (f) of the same figure.
FIG. 9 is a diagram showing a waveform of a detection signal by the drum sensor 75 when the photosensitive drum 79 (79a, 79b, 79c) is an old product having a similar combination configuration.

It should be noted that the timings Ta1 and Ta1 shown in FIGS.
Tb1 and Tc1 indicate the falling time of the detection signal at which the reflection plate 77 is detected by the rotation of the photosensitive drum 79, and are asynchronous signals, respectively.
The initial time is shown aligned so that subsequent waveforms can be easily compared.

Also in this case, the EEPROM 76 stores the detection period of the reflection plate 77 (time Ta1 to Ta2 = Tb1 to Tb).
2 = Tc1 to Tc2) and the detection period (Ta3) of each of the phase / sensitivity marks 83a, 83b and 83c.
デ ー タ Ta4, Tb3〜Tb4, Tc3〜Tc4) and its detection period S (= Ta3〜Ta5 = Tb)
3 to Tb5 = Tc3 to Tc5) are stored, and MP
U71 compares the time data with the time data indicated by the detection signal output from the drum sensor 75 to determine the rotational phase of the photosensitive drum 79, and to determine whether the photosensitive drum 79 is new or old. The determination of the rotation characteristics of each photosensitive drum 79 is also performed at the same time.

FIGS. 6 (d), (e) and (f) show that the reflection plate 77 deviates from the scanning optical path of the drum sensor 75 in the state shown in FIG. 3 (b) because the photosensitive drum 79 is an old product. And the phase / sensitivity mark 83a, 83b or 83c is detected from the beginning. Also in this case, the time ta1 shown in FIGS.
tb1 and tc1 are the phase / sensitivity marks 83a, 83b or 83 due to the start of rotation of the photosensitive drum 79.
Although c indicates the falling time of the detected detection signal, each signal is an asynchronous signal, and the first detection times are aligned so that subsequent waveforms can be easily compared.

FIG. 7 is a flowchart of a processing operation executed by the MPU 71 based on a detection signal from the drum sensor 75 as described above.

FIG. 8 is a table showing the data structure of the data table stored in the EEPROM 76 used by the MPU 71 in the above processing operation. Hereinafter, FIG.
The processing operation executed by the MPU 71 will be described with reference to FIG.

First, when the power of the image forming apparatus is input (step S1), the drum drive motor and the belt drive motor start rotating (step S2). Subsequently, the drum sensor 75 is driven to detect the arrangement of the photosensitive drum (step S3). Then, the outputs of the drum sensors 75 of the black and color photoconductor drums are checked. If the off signal is not output continuously, the black or color photoconductor drum 79 is not mounted, that is, the image is It is determined that the forming unit is not mounted, and a warning is notified to, for example, a display device to mount the image forming unit.

On the other hand, if the output of the drum sensor 75 is an ON signal, the time from when the ON signal is output to when the signal is switched to the OFF signal and the time from when the signal is switched to the OFF signal to when the signal is switched to the ON signal again are detected. (Step S4).

When the ON signal is output from the beginning, the output period of the ON signal is set in advance in the EEPROM.
The rotation time of the reflector 77 stored in the memory 76, that is, the detection period of the reflector 77 shown in FIGS. 6A, 6B, and 6C (time T).
a1−Ta2 = Tb1−Tb2 = Tc1−Tc2), and if they match, it is determined that the photosensitive drum, that is, the image forming unit, is new, and processing according to the newness is performed. Set the mode to do, while
If the output period of the ON signal does not coincide with the detection period of the reflection plate 77 stored in the EEPROM 76, it is determined that the photosensitive drum, that is, the image forming unit is an old product, and
The mode is set so that the processing corresponding to the old product is performed (step S5).

Subsequently, it is further confirmed that the output cycle of the ON signal from the drum sensor 75 is constant, and the ratio (duty) of the output time of the ON signal to the time of one cycle S (see FIG. 6) is calculated. (Step S6). This processing is performed in the fan-shaped phase / sensitivity marks 83a, 83b or 83c provided on the photosensitive drums 79a, 79b and 79c having different sensitivities shown in FIGS. 5 (a), 5 (b) and 5 (c). This is a process for checking which phase / sensitivity mark is detected. One cycle S shown in FIGS. 6 (a), (b), (c) or (d), (e), (f) in FIG. Waveforms Ta3 to Ta4 during the period
(= Ta1-ta2), Tb3-Tb4 (= tb1-t
b2) or a process of calculating the output time of Tc3 to Tc4 (= tc1 to tc2).

The waveforms Ta3 to Ta4 (= ta1 to Ta4)
If the ON signal of ta2) is detected, 15% is calculated as the duty, and the waveforms Tb3 to Tb4 (= tb1 to Tb4) are calculated.
When tb2) is detected, 30% is calculated as the duty, and the waveforms Tc3 to Tc4 (= tc1 to tc4) are calculated.
When c2) is detected, 45% is calculated as the duty.

Next, the drum sensitivity is set based on the duty calculated as 15%, 30%, or 45% (step S7). This process is based on the data table shown in FIG.
Sensitivity data “sensitivity 1”, “sensitivity 2”, or “sensitivity 3” preset in correspondence with “30%” or “45%”
Is extracted, and the extracted sensitivity data is set in a predetermined storage area.

Then, the reference light amount of the optical writing head 23 for exposing the photosensitive drum 79a, 79b or 79c is changed and set based on the set sensitivity data (step S8), and the process is ended (step S9). ).

In the processing for changing and setting the reference light amount of the optical writing head 23, the head light amount correction amount corresponding to the sensitivity data "sensitivity 1", "sensitivity 2" or "sensitivity 3" in the data table shown in FIG. "-5", "0", or "+5"
Is extracted, the reference light amount of the optical writing head 23 is changed using the extracted head light amount correction amount, and the changed light amount is set as a new reference light amount.

As a result, even if the photosensitive sensitivities of the respective photosensitive drums are different, an image having an appropriate density can be output on paper. As described above, in the present invention, in addition to detecting the rotation phase of the photosensitive drum as in the related art using one optical sensor, whether or not a consumable such as a photosensitive unit or an image forming unit is attached, Old and new,
And the sensitivity of the photosensitive drum can be detected.

In the above embodiment, the phase and the sensitivity can be detected by one mark by changing the area of the mark. However, the mark for the phase detection and the mark for the sensitivity are separately provided. You may. This is the third
An embodiment will be described below.

FIGS. 9 (a), 9 (b) and 9 (c) are views showing an example in which a mark for phase detection and a mark for sensitivity are provided separately in the third embodiment. d), (e), (f)
It is a figure which shows the detection waveform of (b) and (c), respectively. FIG.
The photosensitive drums 84 (84) having different sensitivities shown in FIGS.
a, 84b, 84c) are provided with fan-shaped phase marks 85 of the same area, and there is no other mark on the photosensitive drum 84 of sensitivity 1 shown in FIG. The second photosensitive drum 84b is provided with a narrow fan-shaped mark on the opposite side of the phase mark 85, and the photosensitive drum 84c of sensitivity 3 shown in FIG. Two narrow fan-shaped marks are provided on the opposite side of the 85.

In this example, when each of the motors starts rotating when the power of the image forming apparatus is turned on, the MPU is operated in the same manner as described above.
Starts detection of the photosensitive drum. And black,
After detecting the mounting of each color photosensitive drum and detecting the old and new, the detection waveform output from the drum sensor is examined as shown in (d), (e), and (f) of FIG. Phase mark 8
5, a time t1 after the fall of the on / off waveform 86 that has detected the phase mark 5, that is, 1/1 of the detection period S of the phase mark 85.
Whether the falling edge (“L”) of the waveform is detected again at the time of the two cycles, and further, within the detection cycle S of the phase mark 85, a time t2 longer than the time t1 from the falling edge of the waveform 86
Thereafter, it is monitored whether or not the falling edge ("L") of the waveform is detected.

FIG. 10 shows the MPU 71 in the processing in this example.
3 is a table showing a data configuration of a data table stored in an EEPROM 76 used by the ASIC. As shown in the figure, the output of the drum sensor becomes “H” after time t1.
If "H" is maintained after the time t2, the sensitivity data is "sensitivity 1". This is the case where the waveform shown in FIG. 9 (d) is detected, which corresponds to the photosensitive drum 84 shown in FIG. 9 (a).
a. That is, the photosensitive drum 8
"Sensitivity 1" is set in 4a. Since the corresponding head light amount correction amount is "-5", the reference light amount of the optical writing head corresponding to the photosensitive drum 84a is corrected by the above head light amount correction amount "-5".

In FIG. 10, if the output of the drum sensor is "L" after time t1 and "H" after time t2, the sensitivity data is "sensitivity 2". This is shown in FIG.
FIG. 9E shows a case where the waveform shown in FIG.
4B shows the photosensitive drum 84b shown in FIG. That is, “sensitivity 2” is set for the photosensitive drum 84b. Since the corresponding head light amount correction amount is "0", the reference light amount of the optical writing head corresponding to the photosensitive drum 84b is not corrected and remains as it is.

In FIG. 10, if the output of the drum sensor is "L" after time t1 and "L" after time t2, the sensitivity data is "sensitivity 3". This is the case where the waveform shown in FIG. 9 (f) is detected, indicating that it is the photosensitive drum 84c shown in FIG. 9 (c). That is, "sensitivity 3" is set for the photosensitive drum 84c. Since the corresponding head light amount correction amount is “+5”, the reference light amount of the optical writing head corresponding to the photosensitive drum 84c is equal to the above head light amount correction amount “+5”.
5 ".

FIG. 11 is a diagram showing an example of a mark on a photosensitive drum according to the fourth embodiment. As shown in the figure, a bar code area 91 indicated by a broken line is provided on the photosensitive drum 87 on the opposite side of the phase mark 89, and a bar code 92 is applied in the bar code area 91. Also in this case, when each motor starts rotating when the power of the image forming apparatus is turned on, the MPU detects whether or not the photosensitive drum or the image forming unit is mounted, and if so, determines whether the photosensitive drum or the image forming unit is new or old. Thereafter, the rotational phase of the photosensitive drum is detected, and the bar code is read to detect the sensitivity of the photosensitive drum.

In this case, a data table in which the sensitivity data, the light quantity correction value, and the bar code correspond to each other is stored in the EEPROM. Further, in this case, data relating to other characteristics of the photosensitive drum in addition to the sensitivity can be represented by a barcode.

Note that, in the above-described embodiment, any of FIGS.
Is described as a tandem type full-color image forming apparatus similar to the image forming apparatus shown in FIG. 1, but can be applied to other types of electrophotographic image forming apparatuses.

The light amount of the optical writing head is corrected for correcting the difference in sensitivity between the photosensitive drums. However, the correction of the sensitivity is not limited to this, and the high voltage applied to the photosensitive drum from the initialization charging brush may be used. The voltage from the power supply may be corrected.

[0108]

As described above in detail, according to the present invention, the detection of the new and old photosensitive drums can be performed in addition to the detection of the rotational phase by using one phase matching sensor for the photosensitive drum. Therefore, a new or old detection sensor, a switch mechanism, and the like are not required, and the configuration is simplified, and the size reduction and cost reduction of the image forming apparatus main body can be promoted.

Similarly, by using one phase matching sensor for the photosensitive drum, in addition to detecting the rotational phase, the sensitivity set in advance to the photosensitive drum by measurement in advance can be easily determined on the image forming apparatus main body side. This eliminates the need for preprocessing such as test printing for correcting the sensitivity of the photosensitive drum and patch output on the belt, simplifying handling, improving usability, and convenience.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus according to a first embodiment.

2A is a diagram showing a shape of a rotary reflecting plate provided in conjunction with a photosensitive drum of an image forming apparatus, FIG. 2B is a diagram showing a shape of a rotary gear thereof, and FIG. FIG. 6 is a perspective view showing an initial operation state, and FIG. 7D is a side view showing the intermediate operation state.

3A is a perspective view showing a late operation state following the middle operation state of FIG. 2, and FIG. 3B is a side view showing the final operation state.

4A is a diagram illustrating a waveform of a detection signal of a drum sensor when the image forming unit is new, and FIG. 4B is a diagram illustrating a waveform of a detection signal of the drum sensor when the image forming unit is old. FIG.

FIGS. 5A, 5B, and 5C are diagrams illustrating examples of marks provided on a side surface of a photosensitive drum of an image forming apparatus according to a second embodiment.

FIGS. 6A, 6B, and 6C are diagrams showing waveforms of detection signals by a drum sensor when three types of photosensitive drums having different sensitivity characteristics are in a new state, and FIGS. and (f) is a diagram showing a waveform of a detection signal by the drum sensor when an old product is used.

FIG. 7 shows an MPU based on a detection signal from a drum sensor.
6 is a flowchart of a processing operation executed by the.

FIG. 8 is a chart showing a data configuration in a data table in an EEPROM used in processing by the MPU.

FIGS. 9A, 9B, and 9C are diagrams showing examples in which a mark for phase detection and a mark for sensitivity are separately provided in the third embodiment, and FIGS. and (f) show the detected waveforms of (a), (b), and (c), respectively.

FIG. 10 shows EEP used in the third embodiment.
4 is a chart showing a data configuration of a data table stored in a ROM.

FIG. 11 is a diagram illustrating an example of a mark on a photosensitive drum according to a fourth embodiment.

12A is a side sectional view schematically showing the configuration of a main part of a conventional image forming apparatus, FIG. 12B is a perspective view of the photosensitive drum, and FIG. 12C is an operation state of phase information detection. FIG.

FIG. 13 is a side sectional view schematically showing the internal configuration of a conventional full-color image forming apparatus with a drive transmission system not shown.

FIG. 14 is a side view showing a configuration of a drive transmission system in a conventional color printer (full color image forming apparatus).

FIG. 15A is a partially exploded perspective view showing a configuration of a mark and a sensor on a gear side surface of a conventional photosensitive drum, and FIG. 15B is an enlarged view of a part thereof.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Support shaft 2 Photoreceptor drum 3 Charger 4 Optical writing head 5 Toner kit 6 Developing roller P Paper 7 Gear 8 Mark 9 Optical sensor 10 Full-color image forming apparatus (color printer, main unit) 11 Operation panel 12a Open / close paper tray 12b Open / close Discharge tray 13 Paper cassette 14 Upper cover 15 Upper discharge tray 16 Paper transport belt (belt) 17 Drive roller 18 Follower roller 19 (19a, 19b, 19c, 19d) Photoconductor drum 21 Cleaner 22 Initializing charging brush 23 Optical writing Head 24 Developing device 25 Transfer brush 26 Support member 27 Toner 28 Developing roller 29 Tension roller 31 Suction roller 32 Standby roll pair 33 Feed guide path 34 Feed roll pair 35 Feed roller 36 Fixing device 37 Discharge guide path 38 Discharge Roll pair 39 Electrical part 41 41a, 41b, 41c, 41d) Drum gear A1, A2, A3, A4 Drum drive gear B1, B2, B3, B4 Reduction gear C1, C2, C4 Reduction gear 42 Clutch gear 42 Clutch gear 43 Reduction gear 44, 45 Idle gear 46 Drum drive motors 47, 48, 49, 51 Sensor 52 Image forming unit 53 Developing unit 54 Drum unit 55 Unit frame 56 Developing roller shaft 57 Photoconductive drum shaft 58a, 58b Unit receiving portions 58a-1, 58a-2 Bearing portion 59 Gear side surface 61 mark 62, 63, 64 detection hole 70 image forming apparatus 71 MPU 72 drive unit 73 head driver unit 74 optical writing head 75 drum sensor 76 EEPROM 77 reflection plate 78 irregular gear wheel 78-1 rotation axis 78-2 gear 79 (79a 79b, 79c) Photoconductor drum 81 Drum gear 81-1, 81-1a Side surface 81-2 Support shaft 82 Phase mark 83a, 83b, 83c Phase / sensitivity mark 84 (84a, 84b, 84c) Photoconductor drum 85 Phase mark 86 Phase Mark detection waveform 87 Photoconductor drum 89 Phase mark 91 Barcode area 92 Barcode

Continued on the front page (72) Inventor Makoto Asako 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Inside Casio Computer Co., Ltd. (72) Inventor Yukio Akita 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Computer Co., Ltd. Tokyo In-house (72) Inventor Kazutaka Otsuka 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Computer Co., Ltd. Tokyo office F-term (reference) 2H027 DA22 EA01 EA02 ED02 EE07 HB05 HB07 HB14 HB18 ZA07 2H035 CA07 CB03 CG01 2H076 DA22 DA23

Claims (3)

[Claims] A photosensitive drum which is exchangeably disposed on an apparatus main body; a charging means for charging the surface of the photosensitive drum; and a charging means for charging a surface of the photosensitive drum charged by the charging means in accordance with image information. An optical unit that irradiates an optical signal to form an electrostatic latent image, a toner image forming unit that visualizes the electrostatic latent image formed on the surface of the photosensitive drum by the optical unit into a toner image, Transfer means for transferring the toner image visualized by the toner image forming means onto a transfer material to be conveyed; rotation phase information notification means for notifying rotation phase information of the photosensitive drum; and rotation phase information notification Control means for controlling the timing of light signal irradiation by the optical means based on information from the means, wherein the rotation phase information notification means corresponds to the eccentricity of the photosensitive drum. And information corresponding to the sensitivity characteristic of the photosensitive drum, and one detecting means for detecting the information, the amount of charge by the charging means based on predetermined image information or the amount of light irradiation by the optical means An image forming apparatus comprising: a process condition control unit that corrects a value according to a sensitivity characteristic of the photosensitive drum detected by the detection unit and controls the correction value to a preset value. 2. A photoreceptor drum exchangeably disposed on an apparatus main body, charging means for charging the surface of the photoreceptor drum, and a photoreceptor drum surface charged by the charging means according to image information. An optical unit that irradiates an optical signal to form an electrostatic latent image, a toner image forming unit that visualizes the electrostatic latent image formed on the surface of the photosensitive drum by the optical unit into a toner image, Transfer means for transferring the toner image visualized by the toner image forming means onto a transfer material to be conveyed; rotation phase information notification means for notifying rotation phase information of the photosensitive drum; and rotation phase information notification Control means for controlling the timing of light signal irradiation by the optical means based on information from the means, wherein the rotation phase information notification means corresponds to the eccentricity of the photosensitive drum. And information and information corresponding to the old and new states of the photosensitive drum was an image forming apparatus, characterized in that it comprises a single detecting means for detecting the information. 3. A photoreceptor drum exchangeably disposed on an apparatus main body, charging means for charging the surface of the photoreceptor drum, and a photoreceptor drum charged on the surface of the photoreceptor drum according to image information. An optical unit that irradiates an optical signal to form an electrostatic latent image, a toner image forming unit that visualizes the electrostatic latent image formed on the surface of the photosensitive drum by the optical unit into a toner image, Transfer means for transferring the toner image visualized by the toner image forming means onto a transfer material to be conveyed; rotation phase information notification means for notifying rotation phase information of the photosensitive drum; and rotation phase information notification Control means for controlling the timing of light signal irradiation by the optical means based on information from the means, wherein the rotation phase information notification means corresponds to the eccentricity of the photosensitive drum. And information corresponding to the sensitivity characteristics of the photosensitive drum, information corresponding to the old and new states of the photosensitive drum, and one detecting means for detecting the information. Forming equipment.