JP2000221845A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rotary body from being hurt by rotation, by rotating it at a low speed when the rotary body is instructed to be rotated for forming an image in a state in which a door is detected to be open state. SOLUTION: A control part 6 judges via an interface (I/O) 7b whether or not a door switch 3 is open (a door is open), and when the door is closed, it carries out rotation according to a normal instruction via an I/O 7d, and rotates a revolver 110. Before rotating the revolver 110, the control part 6 instructs a warning part 5 to flicker, for example, a warning lamp or sound a buzzer for warning. The control part 6 instructs a driving part for rotating the revolver 110 via the I/O 7d to rotate it at a lower speed than the normal speed and rotates the revolver 110 at the low speed. Further, the control part 6, when the counting time T of a time part 4 reaches a predetermined value T1, instructs the driver via the I/O 7d to rotate the revolver 110 at the normal speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus which prevents a serviceman from being injured.

[0002]

2. Description of the Related Art At present, image forming apparatuses using a rotating body such as a photosensitive drum, a revolver, and a roller are widely used. These image forming apparatuses include the above-described photosensitive drum,
A rotating body such as a revolver and a roller is covered with a protective case so that a user is not injured by rotation of the rotating body.

Further, a door is provided in the protective case. When the door is opened, the power supply circuit is turned off, the operation of all the rotating members is stopped, and the user opens the door when transfer paper jam occurs. The paper has been removed. When a failure occurs in the image forming apparatus, the serviceman opens the door, activates a forced recovery switch that turns off the power supply circuit into an on state, activates the power supply, turns on the rotating body, and recovers the failure. It is carried out.

[0004]

As described above, a serviceman rotates a rotating body at the time of a failure to recover the failure. Therefore, when the rotating body shifts from the stopped state to the rotating state, the hand may be caught between the rotating body and injured.

In particular, a revolver having a color image forming apparatus and a plurality of developing units mounted thereon is heavy and rotates at a high speed. SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus in which injuries due to rotation of a rotating body are eliminated.

[0006]

According to a first aspect of the present invention, there is provided an image forming apparatus protected by a case with a door, the door opening and closing detecting the opening and closing state of the door. When a rotation command is issued to a rotating body for performing image formation in a state where the door is opened by the detecting means and the door opening / closing detecting means, the rotating speed of the rotating body is reduced to a normal low speed. And control means for controlling the rotation of the motor.

In the invention according to claim 2, the control means rotates the rotating body at a normal rotation speed after rotating the rotating body at a low speed for a predetermined time or a predetermined angle. In a third aspect of the present invention, the rotating body is a revolver that rotates with a plurality of developing devices. In the invention according to claim 4, the warning is issued before the rotating body starts rotating at a low speed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a full-color electrophotographic copying machine to which the present invention is applied will be described. FIG. 1 is a schematic configuration diagram of a main part of the printer unit according to the first embodiment. The printer unit is provided with a photoreceptor drum 10 as an image carrier. Around the photoreceptor drum, a writing optical unit as an exposure unit (not shown) and a photoreceptor cleaning device 111 as a cleaning unit When,
A charging charger 13 as charging means, and a revolver developing unit 110 which is a rotary developing device as developing means
And an intermediate transfer unit 120 as an intermediate transfer unit. The printer unit also includes a transfer unit 130 as a transfer unit, a fixing unit 145 as a fixing unit, and a paper supply unit and a control unit (not shown) similar to those in the first embodiment.

The photosensitive member cleaning device 111 includes a fur brush 111 b and a photosensitive member cleaning blade 11.
1c to clean the surface of the photosensitive drum 10 after the primary transfer. Further, the fixing unit 145 includes:
It has a fixing roller pair 145a and a discharge roller pair (not shown).

A solid lubricant 111d as a lubricant is arranged around the fur brush 111b so as to come into contact with the tip of the brush. This solid lubricant 111d
As in the first embodiment, for example, zinc stearate composed of fine particles molded into a plate shape can be used.

The revolver developing unit 110 has a Bk
Developing unit 115, C developing unit 116, and M developing unit 117
And a Y developing device 118, and by rotating the revolver developing unit, a developing position of the developing device of each color which faces the photosensitive drum 10 can be determined.

The intermediate transfer unit 120 includes an intermediate transfer belt 121 serving as an intermediate transfer member, a primary transfer bias roller 122 serving as a charge applying means, a primary transfer power supply 128 serving as a power supply connected thereto, and a primary transfer power supply 128 serving as a power supply. An earth roller 123 as a pre-transfer charge removing unit, a driving roller 124 as a belt driving unit, a tension roller 125,
The configuration is such that the secondary transfer opposing roller 126 and the cleaning opposing roller 127 are stretched. All the rollers that are stretched over the intermediate transfer belt 121 are formed of a conductive material, and each roller other than the primary transfer bias roller 122 is grounded.

The primary transfer bias roller 122 includes
A primary transfer power supply 128 supplies a predetermined primary transfer bias controlled by a constant current or a constant voltage. The intermediate transfer belt 121 has the same configuration as that of the first embodiment, but is formed so that its volume resistivity is 10 ¹² to 10 ¹⁴ Ωcm, preferably 10 ¹³ Ωcm. Also,
The surface resistivity on the surface layer side of the intermediate transfer belt 121 is configured to be 10 ⁷ to 10 ¹⁴ Ωcm.

Around the intermediate transfer belt 121, a lubricant applying brush 129a as a lubricant applying means is provided.
, A belt cleaning blade 129b, and a transfer unit 130, which can be moved toward and away from the intermediate transfer belt 121 by a contact / separation mechanism (not shown).

The transfer unit 130 includes a secondary transfer belt 134 as a transfer material carrier, and a transfer cleaning blade 132 for cleaning the surface of the secondary transfer belt.
, A secondary transfer bias roller 131 facing the secondary transfer facing roller 126 of the intermediate transfer unit 120, a secondary transfer power supply 139 connected to the secondary transfer bias roller 131, and a first support located at an end on the paper feed unit side. Roller 135a and fixing unit 1
There is a second support roller 135b located at the end on the 45 side, a third support roller 135c facing the transfer cleaning blade 132, a transfer paper charge removal charger 136, and a transfer belt charge removal charger 137.

The secondary transfer belt 134 is formed of PVDF and has a volume resistivity of 10 ¹³ Ωcm or more. Note that the transfer unit 130 is not limited to this configuration.
It is also possible to adopt a configuration in which a member having another shape such as a drum is applied instead of.

Next, the operation of the copying machine when the order of development is Bk, C, M, and Y will be described. Before starting the image forming cycle, the photosensitive drum 10 is rotationally driven in the direction of arrow C in FIG. 1, that is, counterclockwise, and the charging charger 113 starts corona discharge. At this time, for example, the photosensitive drum 10 is uniformly charged to a predetermined potential with a negative charge. The intermediate transfer belt 121 of the intermediate transfer unit 120 is driven at the same speed as the photosensitive drum 10, and rotates in the direction of arrow D in FIG. 1, that is, clockwise.

In the scanner section, as in the first embodiment, color image information of a document is read at a predetermined timing, and a laser beam is written by the writing optical unit based on Bk image data obtained from the image information. Optical writing (for example, raster exposure) with light is performed. Thereby, the B corresponding to the Bk image data is displayed on the photosensitive drum 10.
A k latent image is formed. Thereafter, the Bk latent image formed on the photosensitive drum 10 is transferred to the revolver developing unit 110.
Is reversely developed with negatively charged toner. As a result, a Bk toner image is formed on the photosensitive drum 10.

The Bk toner image thus formed on the photosensitive drum 10 is primarily transferred onto the surface of the intermediate transfer belt 121 by the transfer electric field in the primary transfer area. This transfer electric field is formed by electric charges applied to the intermediate transfer belt 121 by the primary transfer bias roller 122. At this time, for example, 1.5 kV for the first color Bk toner image and 1.6 to 1 for the second color C toner image are applied to the primary transfer bias roller 122 by the primary transfer power supply 128. An appropriate primary transfer bias of 1.8 kV to 1.8 kV for the third color M toner image and 2.0 to 2.2 kV for the fourth color Y toner image is applied. . The primary transfer residual toner remaining on the photoconductor drum 10 after development is removed from the photoconductor drum by the photoconductor cleaning device 111.

The image surface on the intermediate transfer belt 121 on which the Bk toner image has been primarily transferred is returned to the primary transfer area again, as in the first embodiment. At this time, similarly to the first embodiment, the lubricant application brush 129a and the belt cleaning blade 129b are separated from the intermediate transfer belt 121 by the respective contact / separation mechanisms so that the toner image is not disturbed.

Further, the first support roller 135a and the secondary transfer bias roller 13 in the transfer unit 130
1 is moved by a transfer contact / separation mechanism (not shown),
The next transfer bias roller is separated from the intermediate transfer belt 121. At this time, the secondary transfer bias roller 1
The application of voltage by the secondary transfer power supply 139 connected to 31 is stopped. The above state is maintained until the toner image primarily transferred on the intermediate transfer belt 121 is secondarily transferred onto transfer paper.

On the other hand, after the above-described Bk process is completed, the C process is started on the photosensitive drum 10 side, and the color image information of the original is read again at a predetermined timing, and the C image data obtained from this image information is read. , A C latent image is formed on the photosensitive drum 10 by a laser beam, and a C toner image is formed by a C developing device 116.

In this embodiment, the rotation operation of the revolver developing unit 110 is started immediately after the trailing end portion of the Bk latent image has passed. This rotation operation is completed before the leading end portion of the C latent image formed on the photosensitive drum 10 reaches the developing position of the C developing device 116. As a result, the C developing device 116 is positioned at the developing position, and the C developing device moving to this developing position is
Develop with toner.

Thereafter, in the M step and the Y step, as in the above-mentioned C step, latent image formation, development, and primary transfer are performed based on the respective image data. In this way, on the same image surface on the intermediate transfer belt 121,
Bk, C, sequentially formed on the photosensitive drum 10
The primary transfer of each of the M and Y toner images forms a toner image in which these four colors overlap on the intermediate transfer belt.

The toner image transferred on the intermediate transfer belt 121 as described above is sent to the secondary transfer area for secondary transfer on the transfer paper 100. At this time, the secondary transfer bias roller 131 of the transfer unit 130
Is pressed against the intermediate transfer belt 121 by a transfer contact / separation mechanism (not shown). Thereafter, a predetermined secondary transfer bias is applied to the secondary transfer bias roller 131 to form a secondary transfer electric field in the secondary transfer area.

Thus, the toner image on the intermediate transfer belt 121 is transferred onto the transfer paper 100. Also,
The transfer paper 100 conveyed to the secondary transfer area is fed at the timing when the leading end of the toner image on the intermediate transfer belt 121 reaches the secondary transfer area.

As described above, the intermediate transfer belt 121
The transfer paper 100 on which the toner images formed by overlapping the four colors are collectively transferred is then transferred to the transfer unit 13.
At 0, the sheet is conveyed to a portion opposite to the transfer sheet discharging charger 136. When passing through the facing portion, the transfer paper is
The transfer paper is neutralized by the transfer paper neutralization charger 136 in the operating state, and is separated from the secondary transfer belt 134. Then, the separated transfer paper is sent between the rollers of the fixing roller pair 145a of the fixing unit 145.

In the fixing roller pair 145a, an unfixed toner image on the transfer paper 100 is melted in a fixing area formed by a nip formed between the rollers, and the unfixed toner image is fixed. Then, the transfer paper is carried out to a copy tray (not shown) and stacked.

On the other hand, the intermediate transfer belt 121 after the secondary transfer
The belt cleaning blade 129b presses the intermediate transfer belt 121 by a belt cleaning contact / separation mechanism (not shown) to remove the secondary transfer residual toner remaining on the surface of the intermediate transfer belt 121. Further, in order to improve the cleaning property and the secondary transfer property, the lubricant accommodated in the lubricant accommodating portion 129c by the lubricant applying brush 129a pressed against the intermediate transfer belt 121 by a contact / separation mechanism (not shown). Is applied.

As the lubricant, for example, zinc stearate composed of fine particles molded into a plate shape can be used. After the transfer paper is peeled off, the charges remaining on the surface of the secondary transfer belt 134 are discharged by the transfer belt discharging charger 137. The surface of the secondary transfer belt 134 is further cleaned by the belt cleaning blade 129b.

FIG. 2 is a schematic structural view of a main part of a printer unit according to a second embodiment, and the same reference numerals are given to the same components as those in the first embodiment. This copier mainly aims at cost reduction, and the structure and operation of the printer section are only slightly different from those of the first embodiment. Therefore, the copier is configured in the same manner as the first embodiment. The description of the operating part will be omitted.

In this embodiment, the intermediate layer of the intermediate transfer belt 221 in the intermediate transfer unit 220 is a medium resistance layer having a volume resistivity of 10 ⁸ to 10 ¹¹ Ωcm. Further, the intermediate transfer belt 221 has 10 ¹⁰
It has a volume resistivity of 〜１０10 ¹² Ωcm. The surface resistivity of the intermediate transfer belt 221 on the surface layer side is:
It is configured to be 10 ⁷ to 10 ¹⁴ Ωcm.

The intermediate transfer belt 221 having such a medium resistance
By using, it is possible to prevent charging unevenness occurring on the surface of the intermediate transfer belt 221 after the primary transfer. Also,
In the present embodiment, the drive roller 224 in the intermediate transfer unit 220 is disposed downstream of the secondary transfer area in the belt rotation direction and upstream of the primary transfer area in the belt rotation direction. By arranging the belt cleaning blade 129b so as to face the drive roller 224, the drive roller also serves as the cleaning counter roller 127 in the second embodiment.

In this embodiment, the transfer unit is replaced by the secondary transfer facing roller 12 of the intermediate transfer unit 220 instead of the transfer unit in the first embodiment.
6 is used. Accordingly, the number of components required for the secondary transfer process is reduced, and the cost can be reduced as compared with the first embodiment.

In the present embodiment, when the paper is fed, the fed transfer paper 100 is directly sandwiched between the secondary transfer bias roller 231 and the intermediate transfer belt 221, and is fixed to the fixing roller pair 145 a of the fixing unit 145. It is sent between the rollers.

Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a block diagram of an embodiment of the present invention, and FIG. 4 is an operation flowchart of the embodiment.
4, reference numeral 10 denotes a photosensitive drum; 110, a revolver developing unit (hereinafter abbreviated as a revolver); 115, a Bk developing device; 116, a C developing device; 117, an M developing device;
Denotes a Y developing device, which is as described in FIG.

In FIG. 3, reference numeral 1 denotes a mark for providing a reference for the rotational position of the revolver developing unit 110, and reference numeral 2 denotes a mark detector for detecting the mark. That is, at the position where the mark 1 is detected by the mark detector 2, each developing device 11
The positional relationship between the photosensitive drums 10, 116, 117 and 118 becomes clear, and the developing units 115, 116, 117
Alternatively, it becomes a reference for giving a rotation angle for making the photoconductor 118 face the photosensitive drum 10.

In FIG. 3, 3 is a door switch provided on a door of a case (not shown), 4 is a timer, 5 is a warning unit, 6 is a control unit, and 7a to 7d are interfaces (I
/ O) and 8 are processors (CPU) for executing processing.

Next, the operation of the embodiment will be described with reference to FIG. In step S1, the control unit 6 sets the I / O 7c
It is determined whether or not the rotation command of the revolver has been transferred via the CPU, and waits until the determination becomes YES. In step S2, the control unit 6 determines via the I / O 7b whether or not the door switch 3 is open (i.e., whether the door is open). Is performed via the I / O 7d, and the revolver 110
To rotate.

In step S5, the control unit 6 instructs the warning unit 5 before rotating the revolver 110, for example, to flash a warning lamp or sound a buzzer to give a warning. In step S6, the control unit 6 instructs a drive unit (not shown) that rotates the revolver 110 via the I / O 7d to rotate at a lower speed than the normal rotation speed, and rotates the revolver 110 at a low speed.

In step S7, the control section 6
And the time T from the start of rotation of the revolver 110 is measured. In step S8, the control unit 6, the counting time T of the timer unit 4 determines whether or not a predetermined value T _1, the process shifts to step S9 when the measured time is T ₁ via the I / O7d revolver 110 Is commanded to rotate in normal rotation.

[0042] In step S10, the control unit 6, measurement time is determined whether or not reached T ₁ is a predetermined value that is T _1, when it reaches the T ₂ of the revolver 110 proceeds to step S11 Stop rotation. The low-speed rotation speed of the revolver 110 in step S6 and the time for performing the low-speed rotation in step S8 are determined in advance by experiments or the like.
The value is set to a value that can be recognized that the revolver is rotating.

[0043] The time T ₂ of the up to stop the rotation of the revolver 110 in step S10 is determined in accordance with the normal operation of the image forming apparatus. That is, FIG. 3 shows a state in which development is performed using the developing device 115, and the developing device 115 and the photosensitive drum 10 are located at positions facing each other. When one job is completed, the revolver 110
Are rotated and stopped at an intermediate position not facing the photosensitive drum 10 and any of the developing devices 115 to 118.

In this state, when the power switch is turned off and then the power switch is turned on, as described above, the revolver 110 rotates in order to know the positional relationship between the photosensitive drum 10 and the developing devices 115 to 118. It rotates and stops until the mark 1 provided on the revolver 110 is detected by the mark detector 2.

Therefore, when the power switch is turned on,
Time to the mark is detected is given as T _2. The rotation of the revolver 110 is not only when the power switch is turned on, but also in these cases, a value corresponding to the operation is set.

In this embodiment, the revolver is rotated at a low speed for a predetermined time T _1. However, an encoder may be used instead of the mark 1 and the mark detector 2 to rotate at a predetermined low speed. Good. In the embodiment, the rotation of the revolver is described, but the rotation can be similarly performed on the photosensitive drum 110 and other rotating bodies.

[0047]

As described above, when the rotating body starts rotating with the door switch open, the rotation speed is set lower than the normal rotation speed, so that the serviceman can easily recognize that the rotation has started. It is possible to prevent injuries from being caught in the rotating body.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part in a printer unit according to a first embodiment to which the present invention is applied.

FIG. 2 is a schematic configuration diagram of a main part of a printer unit according to a second embodiment to which the present invention is applied.

FIG. 3 is a configuration diagram of an embodiment of the present invention.

FIG. 4 is an operation flowchart of the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mark 2 mark detector 3 door switch 4 timer unit 5 warning unit 6 control unit 7 a to 7 d interface (I / O) 8 processor (CPU) 10 photosensitive drum 110 revolver developing unit (revolver) 115 Bk developing unit 116 C developing unit 117 M developing device 118 Y developing device

Claims (4)

[Claims] 1. An image forming apparatus protected by a door-equipped case, wherein: a door open / close detecting means for detecting an open / closed state of the door; and a door open / closed state detected by the door open / close detecting means. An image forming apparatus comprising: a control unit configured to control a rotation speed of the rotator to rotate at a lower speed than normal when a rotation command is issued to the rotator for forming an image. . 2. The image forming apparatus according to claim 1, wherein the control unit rotates the rotating body at a normal rotation speed after rotating the rotating body at a low speed for a predetermined time or a predetermined angle. . 3. The image forming apparatus according to claim 1, wherein the rotating body is a rotating revolver including a plurality of developing units. 4. A warning is issued before the rotating body starts rotating at a low speed.
The image forming apparatus as described in the above.