JPS63193172A - Protecting device for photosensitive drum - Google Patents

Abstract

PURPOSE:To prevent a photosensitive drum from being damaged at the time of handling, by providing a protective cover for covering an exposed part of the photosensitive drum, and also, supported so as to be freely attachable and detachable to and from a unit. CONSTITUTION:A protective cover 117 of a photosensitive drum 32 is formed by plastic, one end part thereof is inserted through a slit 74 provided on a coating cover 71 of a frame 70 supporting the photosensitive drum 32 and a developing device, and also, the other end part is inserted through a slit 70c of the upper part of a guide 70a of the frame 70. According to this constitution, at the time of carrying a unit 31 and at the time of attaching and detaching it to and from the body, damage of the photosensitive drum 32 is prevented by attaching the cover 117, and after the unit 31 is installed to the body, the protective cover 117 is drawn out as it is, and the photosensitive drum 32 becomes a state that an image can be formed.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is applicable to copiers, printers, etc., in which the surface of the photoreceptor drum is The present invention relates to a photoreceptor drum protection device that prevents damage.

(Prior Art) In image forming apparatuses such as electrophotographic apparatuses, during the formation of a large number of images, the characteristics of the photoreceptor drum deteriorate due to wear, chemical changes, etc., which adversely affects two images. Generally, a photoreceptor drum on which a predetermined number of images have been formed is replaced with a new photoreceptor drum. Conventionally, when replacing the photosensitive drum, the photosensitive drum is attached to and removed from the main body by sliding it in the longitudinal direction from the side surface of the main body.

However, in such devices, the surface of the photoreceptor drum is exposed, which is easily contaminated or damaged. When installing or removing the photoreceptor from the main body, there is a risk that the photoreceptor drum may come into contact with surrounding devices and be damaged, or even be contaminated by the operator's hand touching the photoreceptor drum. A problem with the drum is that if it is damaged, the image in that area will be distorted and the image quality will be significantly degraded. Therefore, the operator is required to be very careful when handling the photosensitive drum.

(Problem to be Solved by the Invention) Conventionally, when the photoreceptor drum is attached or removed, its surface remains exposed, so even if the photoreceptor drum is handled carefully, it may come in contact with the surrounding area and be damaged, or the operator may touch it. There is a high risk that the surface of the photoreceptor drum will be damaged, such as fingerprints being deposited on the photoreceptor drum, resulting in a problem of deterioration of image quality.

Therefore, the present invention is intended to eliminate the above-mentioned problems.The surface of the photoreceptor drum is not exposed when it is attached to and removed from the main body, and even if it comes into contact with another device or is touched by an operator's hand, the photoreceptor drum surface is not exposed. It is an object of the present invention to provide a photoreceptor drum protection device that does not damage the drum surface, prevents deterioration of image quality, and further reduces the number of operations required when handling the photoreceptor drum.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a protective cover that is detachably supported by the unit so as to cover the exposed portion of the photosensitive drum.

(Function) According to the above-mentioned means, the present invention attaches a protective cover to the unit to cover the exposed portion of the photoreceptor drum when handling the photoreceptor drum, and at the same time, after the photoreceptor drum is attached to the main body,
By removing the protective cover from the unit and allowing image formation, damage to the surface of the photoreceptor drum is prevented.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 13. First, FIGS. 1 and 2 are front and rear external perspective views of a laser printer main body (10), which is an image forming apparatus of the present invention, and the main body (10) includes an upper cover (11) and a lower seat cover. (12), lower cover (13)
covered with. A stop cover (14) is provided on the upper part of the upper cover (11), and is used on the - side (14) for removing jammed sheet paper or during maintenance.
4a) can be rotated up and down as an axis, while the right side of the upper cover (11) can be opened and closed around its - side (16a) in order to replace the unit (31), which will be described later. A stone wheel cover (16) is provided, and a stone wheel cover (16) is provided on the rear surface of the upper cover (11) to remove paper jams, etc.
A rear vehicle cover (17) is provided that can be opened and closed about a).

Furthermore, an interface connector (18) is provided on the side surface of the lower cover (12) for transmitting and receiving signals from an external computer, word processor, etc. (not shown) that is the host system of the main body (lO), and the rear surface of the lower cover (13) is provided with a power cord (20), a power switch (21), and a ground terminal (22).

Furthermore, a paper feed section (24) into which a removable paper feed cassette (23) is inserted is provided at the lower front of the main body (lO), and a paper output tray (26) is removably attached above it. There is. Furthermore, a control panel (27) consisting of an indicator lamp and a switch is provided on the front surface of the upper cover (11).

Next, FIG. 3 shows the inside of the main body (10), which is an image carrier with a diameter of approximately 3.
A charging device ffl (33) consisting of a scorotron charger, a laser optical system (34), and a photoreceptor drum (32) are incorporated into the unit (31) around the photoreceptor drum (32) of 0 (mm). A transfer device i! consisting of a developing device (36) that performs development and cleaning at the same time, an irradiation lamp group @ (76), and a corotron charger. (37) and a static elimination lamp (38) are arranged in this order. Furthermore, the main body (1
0) At the tip of the paper feed cassette (23) at the bottom, there is a paper feed roller (40
) is provided so as to be able to come into contact with the sheet paper (41) which is the transfer material, and the uppermost sheet paper taken out from the paper feed cassette (23) by the separation claw (23a) is moved to the first sheet paper guide. Paper is fed to aligning rollers (43a) and (43b) via (42a) and (42b). or.

In front of the aligning rollers (43a) and (43b), there is a first magnet (44a) having a first magnet (44a) at the other end.
lever (44b) and the first reed switch (44c)
) The first paper detection device consisting of! (44) is provided. Furthermore, an aligning roller (43) is provided above the main body (10).
a), a second sheet paper guide (46) forming a conveyance path for the sheet paper (41) reaching the paper output tray (26) from (43b), intermediate rollers (47a), (47b),
A third sheet paper guide (48), a fixing device (52) consisting of a heat roller (50) that has a built-in heater (50a) and whose temperature is detected by a thermistor (SOB) and a press roller (51), and a paper ejection roller ( 53a), (53b)
is provided. In addition, the paper ejection roller (53a), (
53b), there is a second magnet (54a) at the other end.
A second paper detection device (54) is provided, which includes a second lever (54b) having a second lever (54b) and a second reed switch (54c). Note that (55) is a control unit that controls each image forming apparatus, control panel (27), and the like.

Among the above devices, the laser optical system (34) uses a laser beam (
A polygon mirror (60) that is rotated at high speed by a mirror motor (61) in order to scan the laser diode (60) that oscillates a laser beam (60a) that is oscillated and focused by a collimator lens or a compressor lens (not shown). 62), and the laser beam (60a) reflected by the polygon mirror (62) is further transferred to the photoreceptor drum (32).
It consists of a lens system (63) that irradiates the area.

Next, a unit (3 types) that is equipped with a photoreceptor drum (32) and a developing device (36) will be described in detail. The frame (70) includes a rail (10a) within the main body (10),
The photosensitive drum (32) and the developing device (36) can be attached to and detached from the main body (10) freely by the first guide (70a) and the second guide (70b) that fit into the photosensitive drum (32) and the second guide (70b).
While supporting.

The covering cover (71) on the top surface, which also serves as the lid of the developing device (36), is part of a conveyance path for conveying the sheet paper (41) to the transfer position together with the second sheet paper guide (46). The covering cover (71) is also inclined so that the conveyance direction of the sheet paper (41) is inclined inward from the tangential direction of the photoreceptor drum (32). In addition, the upper surface of the covering cover (71) is provided with ribs (71a) to reduce friction with the sheet paper (41).
A lower intermediate roller (47b) is biased upwardly by a leaf spring (not shown) so as to follow an upper intermediate roller (47a) connected to a drive unit (not shown).
)have. Also inside this bottom side.

Both sides of the intervening roller (47b) are largely chamfered so as to prevent attachment and detachment of the unit (31). Again (72)
is a handle used when transporting the unit (31), and is rotatably attached to the attachment part (72a), and when in use is taken out from the recess (73) formed in the cover (71). ) When installing to the rib (7
1a) is housed in the recess (73) so as not to protrude further;
Furthermore, the upper part when stored is formed into a cylindrical shape to reduce resistance with the paper sheet (41).

Note that (74) is a protective cover (11) for the photoreceptor drum, which will be described later.
This is a slit that supports the negative side of 7). Further, an irradiation lamp device (76) is provided at the tip of the covering cover (71).

The photoreceptor drum (
32) The entire surface is irradiated with light. In addition, the irradiation window (71
b) is made of felt and has a photoreceptor drum (32
) A cleaner (77) is attached that cleans both ends and also serves as a rotation brake.

On the other hand, on the rear end side of the covering cover (71) there is a developing device rrl (3
6) a supply port (78) for supplying toner is formed in the interior;
A cup (not shown) connects the toner hopper (
When the toner hopper (79) is attached, the toner hopper (79) can be opened, and when the toner hopper (79) is removed, the toner hopper (79) is biased by a spring (not shown) and closed. In addition, (75a) and (75b) cover the cover (71) to the side frame (82a) and (82
Holes (80a), (80b), and (80b) formed in b)
(80c) and (80d) are holes for screwing.

Next, the developing device (36) will be described in detail. (81) is a developing roller, and the distance from the photosensitive drum (32) is approximately 2.
[l] Side frame (82a), (8
2b) is supported. That is, a three-pole magnetized magnet roller (84) is provided inside the aluminum sleeve (83), which is a sleeve-shaped conductive roller with a diameter of 30 (+a+s), of the developing roller (81), and the photoreceptor drum ( 32), the first pole (84a) is substantially opposite to the magnetic force 9
50 to 1050 (G), and this first pole (84a
) clockwise at intervals of 75 [degrees], magnetic cuff 00 [G]
The second pole (84b) has a magnetic force of 500 (G), and the third pole (84b) has a magnetic force of 500 (G).
c). Further, at the drive side end of the developing roller (81), as shown in FIG.
A flange (86) supporting the aluminum sleeve (85) is press-fitted to maintain good electrical continuity between the aluminum sleeve (83) and the conductive shaft (85). The center of the conductive shaft (85) is contacted at one point by a spring (88a) supported by the main frame (87).
A power supply blade (88) that applies a developing bias to the aluminum sleeve (83) by a power supply (88b) is in contact with the power supply blade (88). Note that (90) is a bearing that supports the conductive shaft (85) in the side frame (82a);
91) rotated the aluminum sleeve (83) via the conductive shaft (85).

The 0th gear (92), which is the first gear, is the developer container (93).
) Approximately 1.8 (0111
) is a doctor blade installed through the gap.

The attachment is fixed by a screw (94) which is a member. The tip of the doctor blade (92) is located at an intermediate portion between the second pole (84b) and the third pole (84c) of the magnet roller (84), where the lines of magnetic force are approximately parallel to the developing roller (81); Furthermore, a magnetic brush (not shown) is formed using a developer consisting of negative polarity toner and carrier.

It is provided at a position almost parallel to the developing roller (81). Therefore, even if the height of the magnetic brush is regulated by the doctor blade (92), the stress on the developer can be made relatively small, which in turn reduces the driving torque required to rotate the aluminum sleeve (83). I try to do that.

The screw (93) is a screw (91) through which the developer leaking from the developer container (93) is inserted from the outside of the developer container (93).
There is a risk that the attached developer will be influenced by the magnetism of the magnet roller (84), form a column, and come into contact with the main body (10), resulting in leakage of the developing bias current. In order to prevent this, it is made of an insulating and non-magnetic plastic material.

Next, (100) and (101) move the developing roller (81) while stirring the developer (not shown) in the developing container (93).
) of non-magnetic conductive material (SUS30
4 (stainless steel)]. The first spiral (100) adjacent to the developing roller (81) has an outer diameter of 18 (
m+wl continuous spiral first blade (100a)
is wound around a first spiral shaft (100b).

On the other hand, the second spiral (101), which is separated from the first spiral (100) by a partition wall (103) made of an aluminum plate with a thickness of 0.8 [■■], has a minimum outer diameter of 24
[mm] A plurality of second blades (101a) in the shape of a long circular plate cut in half are attached to a second spiral shaft (
101b) so that the directions alternate by half a turn. That is, in the second spiral (lot), new toner supplied from the supply port (78) is sufficiently stirred with the developer in the developer container (93), while the new toner is supplied to the first spiral (100). If so, the second spiral (i
Although it does not have as much stirring power as oi), it has a small diameter,
It has almost the same conveying force as the No. 2 spiral (101). In addition, the first and second spirals (
100) and (101) are for preventing both spirals (100) and (101) from being magnetized by the magnetic field of the developing roller (81) and inhibiting the movement of the developer.

It is made of Sυ5304 [stainless steel], a non-magnetic conductive material. Further, the partition wall (103) has a second spiral (101) at the end opposite to the supply port (78).
A conduction port (103a) is formed for conveying the developer from the side to the first spiral (100) side. still,
The height of the partition wall (103) is the same as that of the developing roller (81) after development.
It is necessary that the developer that should be dropped onto the first spiral (100) does not jump over to the second spiral (101) side. This is to prevent the amount of developer on the second spiral (101) side from increasing due to the developer jumping from the developing roller (81) to the second spiral (lot) side. Furthermore, the first spiral (
100) and the drive side end of the second spiral (101), each spiral shaft (100b).

(101b) is supported by the side frame (82) via a bearing (not shown), and the drive from the main motor (not shown) of the main body is transmitted to the end of the first spiral shaft (100b). A gear (104) is attached to the end of the second spiral shaft (101b), and a second gear (106) that meshes with the gear (104) is attached to the end of the second spiral shaft (101b). Furthermore, the gear (104) has a first gear (
A third gear (107) which rotates the aluminum sleeve (83) is meshed with the third gear (107). Also gear (
104) A cylindrical part (104a) is provided at the end, and a 13 [bit] barcode-like binary pattern is printed on it, which is an identification number for each individual unit, so that 8192 (individuals) units can be identified. A sticker (108) is attached.

The binary pattern on this sticker (108) is read by a photoelectric sensor (not shown) installed on the main body side and consisting of a light emitting diode and a phototransistor. On the other hand, a storage section (not shown) in the control section (55) that does not disappear even when the power switch (21) is turned off stores the identification number read by the photoelectric sensor (not shown) and also stores the identification number read by the photoelectric sensor (not shown). The control unit (55) stores the number of sheets printed in each unit, determines the number of sheets remaining in each unit's lifespan, and when the number of sheets printed reaches a preset number of sheets in its lifespan, the controller (55)
This is displayed on the control panel (27).

Next, the photoreceptor drum (32) will be described in detail. Flanges are fitted into both ends of the photoreceptor drum (32), and a leaf spring (1
A spring clutch (112) which is a one-way clutch is provided, and a drive transmission section (11) is provided.
09) is formed. Further, a protrusion (110b) provided around the hole (110a) in the center of the flange (110).
However, the bearing (113) provided on the side frame (82)
).

- On the strength tree body side, a drive shaft (114) connected to a main motor (not shown) is provided, and when the unit (31) is attached to the main body, the drive shaft (114) is connected to the flange (110). is inserted into the hole (110a) and fitted into the spring clutch (112), so that its drive can be transmitted to the photosensitive drum (32) via the flange (110), and comes into contact with the leaf spring (111); It will be electrically connected to the photosensitive drum (32). The photoreceptor drum (32) is connected to the developing roller (81) in the unit (31).
) and one side provided with a gap of approximately 2 (mm).

The gap between the tip of the covering cover (71) and the frame (7
The gap with the member (116) provided at the tip of the device (116) for preventing the developer from scattering is approximately 0.3 mm.6 Furthermore, (117) is a protective cover made of plastic, and the - side is A slit (7) formed in the cover (71)
4) and the other side is inserted into the first part of the frame (70).
A slit (70c) formed in the upper part of the guide (70a)
), and is worn when transporting the unit (31) and when installing and removing it from the main body, but is removed after the unit (31) is installed.

Also, (118a) and (118b) are knee 1-t (3
This bottle is inserted from the side frame (82b) on the non-rFA moving side of 1) to seal the developer in the developer container (93) during transportation, and the unit (31) is inserted into the main body (10).
It must be removed after being attached to the device.

Note that (121a), (121b), and (121c) are holes into which pins (not shown) on the main body side are inserted in order to position the unit (31) within the main body (10).

Next, we will discuss the operation. When the power switch (21) of the main body (10) is turned on, the control section (55) controls the main body (10) while rotating the drive source (not shown) for a certain period of time.
Check the condition of each part, and if there is any abnormality, turn on the warning lamp (not shown) on the control panel (27), etc.
Display this to the operator. On the other hand, if there is no abnormality,
The control unit (55) controls the heater (50a) built into the heat roller (50) of the fixing device (52).

The temperature detected by the thermistor (50b) is 220
The heater (50a) is turned off until the temperature of the heat roller (50) reaches 220 [°C], and then the temperature of the heat roller (50) reaches 180 [°C]. When the temperature reaches the appropriate temperature, the heater (50a) is turned on again and the temperature of the heat roller (50) is 180 ('C) to 220 ['C].
While the heater (50a) repeatedly blinks to maintain the print status, a message indicating that printing preparation is completed and waiting for printing is displayed on the control panel (27) and transmitted to the host system (not shown). do.

In this state, a command to start printing is sent from the host system (not shown) and printing is started.

The control unit (55) first operates a mirror motor drive circuit (not shown) to rotate the mirror motor (61).

And the polygon mirror (62) has a constant rotation speed of 60
When the rotation becomes stable at 00 [7 minutes of rotation], the mirror motor drive circuit (not shown) transmits this to the control section (55).

Thereafter, the control unit (55) operates a main motor drive circuit (not shown) to rotate the main motor (not shown) and rotate the drive shaft (114) to rotate the photoreceptor drum (32). while rotating the other developing roller (
81) and so on. At the same time, the control unit (55) operates the charging device (33), the static eliminating bag (37), etc. As a result, the photoreceptor drum (32) rotates in the direction of arrow S and is first uniformly negatively charged by the band type device (33) so that the surface potential becomes 600 (V). On the other hand, in the laser optical system (34), a laser beam (60a) is emitted from a laser diode (60) based on print data from a host system (not shown).
) is focused by a collimator lens or compressor lens (not shown), and then enters a polygon mirror (62) that is stably rotated at 6000 [rotation time: 7 minutes] so that it is scanned in the longitudinal direction of the photoreceptor drum (32). be done. The laser beam (60a) reflected by the polygon mirror (62)
) is irradiated onto the photoreceptor drum (32) uniformly charged to about 600 (V) through the lens system (63), forming an electrostatic latent image on the photoreceptor drum (32). . However, in the lens system (63), the laser light (60a) from the polygon mirror (62) is focused into a spot of about several tens of microns and irradiated onto the photosensitive drum (32). Thereafter, the photosensitive drum (32) carrying the electrostatic latent image reaches the developing section rR (36) as it rotates, but the TfL image device (
36), development and cleaning are performed as follows. That is, in the developer container (93), there is a gear (104) to which the drive from the main motor (not shown) is transmitted.
and the first spiral (1) by the second gear (106).
00) and the second spiral (101) are rotated in the direction of the arrow and the direction of the arrow U, respectively, and the first spiral is rotated by the gear (104) via the third gear (107).
The aluminum sleeve (83) is rotated in the direction of arrow V by the gear (91). Then, new toner is supplied onto the second spiral (101) in the developer container (93) from the toner hopper (79) through the supply port (78), and the second spiral (101) first converts it into developer. The developer is transported in the direction of arrow W within the developer container (93) while being sufficiently stirred, and the well-stirred developer is transferred to the first spiral (1
00), the developing roller (8
1) side, and a magnetic brush is formed on the aluminum sleeve (83). Furthermore, aluminum sleeve (
83), a bias voltage of approximately 400 (V) having the same polarity as the charging voltage of the photoreceptor drum (32) is applied from the power supply blade (88) via the flange (86) having the conductive shaft (85). has been done.

Then, the electrostatic latent image area of the photoreceptor drum (32) is transferred to the developing area @
(36), the toner has negative polarity in the non-exposed area where the surface potential (-) 600 [Vl is maintained.

Since the surface potential is greater than the bias potential (-) 400 (V), the developing roller (81) to the photoreceptor drum (32)
However, if there is residual toner in this non-exposed area, the surface potential (-)
600 (Vl and bias potential (-) 400 (V)
(7) Due to the potential difference, the residual toner is removed from the developing roller (8).
1), and the photosensitive drum (32) is cleaned. on the other hand.

In the exposed area where the surface potential of the photoreceptor drum (32) is approximately 0 (V), the developing roller (to which a bias voltage is applied) is
The toner is transferred to the developing roller (81) due to the potential difference between the developing roller (81) and
1), the image is transferred to the photoreceptor drum (32) and developed. Thereafter, the entire surface of the photoreceptor drum (32) is exposed by the irradiation lamp device (76) as the photoreceptor drum (32) rotates.

After being neutralized, it reaches the transfer device (37). On the other hand, in the paper feed section (24), after driving the main motor (not shown), the paper feed roller (
40) is rotated once, and the uppermost sheet paper (41) is taken out from the paper feed cassette (23). and sheet paper (
41) is the first sheet paper guide (42a), (4
2b), the first lever (44b) is actuated to turn the first reed switch (44c) from on to off, and the sheet paper (41) is sent to the control unit (55) from the first paper detection device (44). After displaying that it has arrived, it reaches the stopped aligning rollers (43a) and (43b) and is temporarily stopped. Thereafter, the control unit (
55) are aligning rollers (43a) and (43b).
) starts driving.

Second sheet paper guide (46), intermediate roller (47a)
.

(47b), the sheet paper (41) is transferred to the transfer device (37
). When the developing section of the photoreceptor drum (32) and the sheet paper (41) reach the transfer bag fi (37), a positive charge with the opposite polarity to the toner is applied by the transfer device (37), and the sheet paper (41) is charged onto the photoreceptor drum (32). The toner image is transferred to the sheet paper (41). Next, the sheet paper (41) is peeled off from the photoreceptor drum (32) and moved to the third sheet paper guide (
48) and reaches the fixing device (52), but since the photoreceptor drum (32) is small with a diameter of about 30 mm, the sheet paper (41) is removed without using a peeling device such as a peeling claw or a peeling charger. The photoreceptor drum (32
) It peels off more naturally. The sheet paper (41) is fixed by the fixing device (52) in which the surface temperature of the heat roller (50) is maintained between 180 ('C) and 220 [''C], and then the second lever (54b) ), the second reed switch (54c) is turned from on to off, and the second paper detection device (54) detects that the sheet paper (41) has arrived.
) is displayed on the control unit (55), and the output roller (53a)
, (53b) onto the paper discharge tray (26). Then, the sheet paper (41) is detected by the second paper detection device (
54), the second reed switch (54) is completely passed through.
4c) is returned from the off state to the on state, and the control unit (
55) indicates that the sheet paper (41) has been ejected.

Also, during this time, the photosensitive drum (32) that has passed through the transfer device (37) is entirely exposed to light by the static elimination lamp (38).
The residual charge is removed and the next printing is made possible.

When all the printing processes are completed in this way, the control section (5
5) stops other devices except for temperature control of the heat roller (50) and waits for the start of the next printing, after which printing starts sequentially in response to printing commands from the host system (not shown). It means repeating the process.

During this time, the control section (55) stores the identification number of the unit (31) using a binary pattern on the sticker (108) read by a photoelectric sensor (not shown), and each time the printing process is completed, The number of printed sheets is sequentially added to the number of printed sheets from the start of use of the unit (31). When the number of printed sheets reaches the preset lifetime number of sheets, 2 [1 sheet], the control section (55) displays this on the control panel (27).

As a result, the operator recognizes that the unit (31) has exceeded its usage limit, and in order to replace it with a new unit, first open the right small cover (16) of the main body (10) and remove the first guide ( 70a) and second guide (70b)
Pull out the frame (70) along the line and take out the used unit (31). At this time, on the drive side of the unit, the gear (104) meshes with the gear on the main body side (not shown), and the photosensitive drum (32) is connected to the leaf spring (111) and the spring clutch (112). The spring clutch (112) is fitted to the drive shaft (114) through the drive shaft (114), but since the fitting force of the spring clutch (112) in the axial direction of the drive shaft (114) is only the frictional force corresponding to the tightening third of the spring, Only by resisting the pressing force of the leaf spring (111) and the frictional force of the spring clutch (112),
The photoreceptor drum (32) and thus the unit (31) can be inserted and removed from the drive shaft (114) relatively easily.

Next, the operator installs a new unit (31) with the exposed part of the photoreceptor drum (32) still covered with the protective cover (117) into the main body (10), but at this time, the operator uses the handle that was used during transportation. (72) is stored in the recess of the covering cover (71). Then, the first guide (70a) and the second guide (70b) are connected to the rail (
10a) and (10b), the drive shaft (114) is inserted into the flange of the photoreceptor drum (32), and the pin (not shown) on the main body side of 5 is inserted into the hole (10b).
21a).

(121b) and (121c), and the unit (31) is attached to the main body (10) so that the power supply blade (88) comes into contact with the conductive shaft (85).

Furthermore, the operator slides the protective cover (117) along the slits (70c) and (74) and pulls it out of the main body (io) through the opening of the right small cover (16) to open the photosensitive drum (32). A pin (118a) is used to make the developer (102) usable and to prevent the developer (102) from scattering.
).

(118b) is also removed, the unit (31) is made usable, the right small cover (16) is closed, and printing is resumed. Further, when the gear (104) is rotated by the drive of the main motor (not shown), a photoelectric sensor (not shown) in the main body causes the seal (108) to be affixed to the cylindrical part (104a). The binary pattern is read,
A new identification number of the newly installed unit (31) is stored in the control section (55). In the control unit, the number of printed sheets for each recognition number is stored in sequence according to the printing. For example, even if a unit that has already reached the end of its lifespan is accidentally reinstalled into the main unit, it will be recognized immediately. When the number is read, the control section (55) recognizes that the unit prints the number of sheets that have reached the end of its life and is used, and displays this on the control panel (27). In addition, the removed protective cover (117) should be used again when attaching or detaching the unit (31) during maintenance.
) and save it for attachment.

With this configuration, when the unit (31) is attached or detached, the protective cover (117) can be attached to the photoreceptor drum (3
2) can be covered and protected, and after the unit (31) is installed, by removing the protective cover (117) in the longitudinal direction, the photoreceptor drum (32) can be easily made ready for image formation. When handling the product, the operator may touch the photosensitive drum (32).

Alternatively, even if the photoreceptor drum (32) comes into contact with the surrounding equipment, the photoreceptor drum (32) will not be damaged, and the deterioration of image quality will be prevented. The operator does not have to worry about conventional devices when attaching and detaching the device, making it easier to handle.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified in various ways.For example, the number of life spans of the unit, etc.

The size and polarity of the charging position of the image bearing member or the developing bias of the developing roller can be set arbitrarily, and the diameter of the spiral can also be set at the secondary position.
The size is not limited as long as the diameter of the first spiral is larger than the diameter of the first spiral.

Furthermore, the shape of the spiral blades is arbitrary, and the second spiral blades may also be continuous or spiral-shaped like the first spiral, but in this case, the first spiral and the second
In order to equalize the amount of developer conveyed by the spiral,
In the second spiral, blades in the opposite direction may be installed to prevent the conveyance of the developer.Also, the device for identifying individual units is one that reads the pattern using a photoelectric sensor. Instead, the covering cover (127) of the unit (126) as in the other variant shown in FIG.
At the end of each unit, a resistance element (128) with a diameter varying from several [ohms] to several [ohms] is installed, while on the main body side, when the unit (126) is installed, the resistance element (128)
) is connected to the connector terminal (128a) and reads the resistance value as a voltage. It may be a device that stores the information and counts the number of images for each unit. Furthermore, when the unit prints reaches its lifespan.

The image formation may be stopped immediately. Also, although the developing device in the embodiment is a developing device that performs development and cleaning at the same time, the present invention is not limited to this, and may be a device that performs only development. It's okay.

〔Effect of the invention〕

As explained above, according to the present invention, when handling the photoreceptor drum, the exposed part can be covered and protected by the protective cover, so that there is no need to touch it with your hands or come into contact with other devices during handling. Since the photoreceptor drum is covered with a protective cover, there is no risk of damage to the photoreceptor drum, which in turn prevents deterioration of image quality.Furthermore, the operator does not have to pay attention to the handling of the drum as in the past. Improved operability. On the other hand, after the photoreceptor drum is attached to the main body, the protective cover can be removed without changing the state, and the photoreceptor drum can be easily brought into an image forming state.

[Brief explanation of the drawing]

Figures 1 to 13 show one embodiment of the present invention; Figure 1 is an external perspective view of the main body from the front, Figure 2 is an external perspective view of the main body from the rear, and Figure 3 is the main body. Figure 4 shows the unit, A) is a schematic explanatory diagram of the inside, (B) is a partially enlarged view of (A), Figure 4 is a perspective view of the unit, and (B) is a perspective view of the cover. A perspective view showing the frame, FIG. 5 is a partial sectional view showing the developing roller and its power supply blade, FIG. 6 is a sectional view showing the unit and the rail of the main body, and FIG. 7 shows the first spiral. FIG. 8 is a partially omitted side view showing the second spiral, FIG. 9 is a schematic explanatory diagram showing the circulation of the developer in the developer container, and FIG. 10 (A) is a partially omitted side view. A schematic sectional view showing the drive side end of the photosensitive drum, FIG. 10(B) is a sectional view showing the drive transmission section, FIG. 11 is a side view showing the non-drive side of the unit, and FIG. FIG. 13 is a side view showing a pin for sealing the inside of the developer container, and FIG. 14 is a perspective view showing another modification. , 10... Main body, 23... Paper feed cassette, 26... Paper output tray, 31...
·unit. 32... Photosensitive drum, 33... Charging device, 34... Laser optical system, 36... Developing device, 37... Transfer device, 38... Static elimination lamp, 41... Sheet paper , 47a,
47b... intermediate roller, 52... fixing device,
55...control unit, 70...frame,
71... Covering cover, 71a... Rib,
72...handle. 76... Irradiation lamp device, 81... Developing roller, 83... Aluminum sleeve, 84... Magnet roller, 85... Conductive shaft, 88
...Power supply blade, 92...Doctor blade, 9
3...Developer container, 94...screw; 100...first
Spiral, 101...Second spiral, 1
03... Bulkhead.

Claims (1)

[Scope of Claims] 1. In a device in which a photoreceptor drum is slid in the longitudinal direction to be attached to and removed from the main body, a unit that holds the photoreceptor drum, and a unit that is parallel to the longitudinal direction of the photoreceptor drum. 1. A photoreceptor drum protection device comprising: a support portion formed in the photoreceptor drum; and a removable protective cover that is slidably attached to the support portion and covers an exposed portion of the photoreceptor drum. 2. The photosensitive drum protection device according to claim 1, wherein the support portion is a slit, and an end portion of the protective cover is inserted through the slit.