CN111221230B - Image forming apparatus and computer-readable recording medium - Google Patents
Image forming apparatus and computer-readable recording medium Download PDFInfo
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- CN111221230B CN111221230B CN201911153476.8A CN201911153476A CN111221230B CN 111221230 B CN111221230 B CN 111221230B CN 201911153476 A CN201911153476 A CN 201911153476A CN 111221230 B CN111221230 B CN 111221230B
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
- G03G15/0258—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices provided with means for the maintenance of the charging apparatus, e.g. cleaning devices, ozone removing devices G03G15/0225, G03G15/0291 takes precedence
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
- G03G21/06—Eliminating residual charges from a reusable imaging member
- G03G21/08—Eliminating residual charges from a reusable imaging member using optical radiation
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Abstract
The invention provides an image forming apparatus and a control program of the image forming apparatus, which can inhibit the reduction of the service life of a photoreceptor. The image forming apparatus includes: a photoreceptor (22); and an eraser unit (25) which removes electrons from the surface of the photoreceptor (22) by irradiating the surface of the photoreceptor (22) with erasing light between the time of transfer of the toner image formed on the surface of the photoreceptor (22) and the time of charging for forming the next toner image. The image forming apparatus adjusts the amount of erasing light (ES) based on at least one of information on a toner image formed on the surface of a photoreceptor (22) after electrons are removed from the surface of the photoreceptor (22) by an eraser unit (25) and a setting accepted from a user of the image forming apparatus.
Description
Technical Field
The present invention relates to an image forming apparatus and a control program for the image forming apparatus. More specifically, the present invention relates to an image forming apparatus and a control program for the image forming apparatus, which can suppress a decrease in the lifetime of a photoreceptor.
Background
Some electrophotographic image forming apparatuses include an MFP (Multi Function Peripheral) having a scanner Function, a facsimile Function, a copy Function, a printer Function, a data communication Function, and a server Function, a facsimile apparatus, a copier, a printer, and the like.
In general, an image forming apparatus forms an image on a sheet by forming a toner image by developing an electrostatic latent image formed on a surface of a photoreceptor by a developing device, transferring the toner image to the sheet, and fixing the toner image to the sheet by a fixing device. Further, there are also in the image forming apparatus: a developing device develops an electrostatic latent image formed on a surface of the photoreceptor to form a toner image, and the toner image is transferred to an intermediate transfer belt by a primary transfer roller and the toner image on the intermediate transfer belt is secondarily transferred to a sheet by a secondary transfer roller. Further, the image forming apparatus removes toner remaining on the surface of the photoreceptor after transfer using a photoreceptor blade.
If the potential of the surface of the photoreceptor before charging is greatly different depending on the position of the surface of the photoreceptor, a potential difference is generated also on the surface of the photoreceptor after charging. When development is performed in a state where a potential difference exists on the surface of the photoreceptor after charging, image shading occurs due to the potential difference on the surface of the photoreceptor. The shading of an image due to a potential difference on the surface of the photoreceptor is called memory ghost (memory ghost). In order to prevent the occurrence of memory ghosting and suppress the degradation of image quality, the image forming apparatus is provided with a charge removing device. The static elimination device irradiates a surface of the photoreceptor after transfer and before charging with a certain amount of erasing light, thereby removing electrons remaining on the surface of the photoreceptor after transfer and eliminating a potential difference existing on the surface of the photoreceptor after transfer.
Patent documents 1 to 3 listed below disclose techniques for controlling erasing light of a static eliminator. Patent document 1 below discloses an image forming apparatus including: a charge removing unit that irradiates a charge removing light to the surface of the photosensitive drum before charging and removes the charge remaining on the surface of the photosensitive drum after transfer; and a control means for making the quantity of light excluding the electric light in the range of formation of the toner image in the direction of rotation of the photosensitive drum weaker than the quantity of light in the range of formation of the toner image.
Patent document 2 listed below discloses an image forming apparatus including an erasing lamp for removing charges remaining on the surface of a photoreceptor drum after transfer, wherein when a latent image pattern region formed by exposing the surface of the photoreceptor drum based on image data reaches an irradiation region of the erasing lamp, the erasing lamp is turned off in a region where charge removal is unnecessary with reference to the image data for exposure.
Patent document 3 listed below discloses an image forming apparatus in which a charge removing light amount control means for changing the amount of light emission in accordance with the operating state is added to a drive control unit of a light source lamp of a charge removing unit. The charge removing amount control means includes control means for changing the amount of light emitted from the light source lamp based on the output of a temperature sensor provided in the fixing section, or image property determination means for roughly grasping the white amount or the black amount or the ratio of the white amount to the black amount of the image data at the time of printing, and control means for changing the amount of light emitted from the light source lamp based on the determination result of the image property determination means with respect to the image data printed immediately before.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2011-145325
Patent document 2: japanese patent laid-open publication No. 2009-271358
Patent document 3: japanese patent laid-open No. 08-328437
Disclosure of Invention
When a certain amount of erasing light is irradiated from the static elimination device, the potential of the surface of the photoreceptor before charging is always reduced to a low level. This also increases the discharge energy of electrons necessary to charge the surface of the photoreceptor again after the charge is removed. When the discharge energy of electrons during charging is increased, the surface of the photoreceptor receives a large impact due to discharge, and the progress of abrasion of the surface of the photoreceptor is accelerated, which causes a problem that the life of the photoreceptor is reduced.
The present invention has been made to solve the above problems, and an object thereof is to provide an image forming apparatus and a control program for the image forming apparatus, which can suppress a decrease in the lifetime of a photoreceptor.
An image forming apparatus according to an aspect of the present invention includes: a photoreceptor; a charge removing member that removes electrons from the surface of the photoreceptor by irradiating the surface of the photoreceptor with erasing light between the time of transfer of a toner image formed on the surface of the photoreceptor and the time of charging for forming the next toner image; and an optical adjustment member that adjusts the amount of erasing light based on at least one of information on a toner image formed on the surface of the photoreceptor after electrons are removed from the surface of the photoreceptor by the charge removal member and a setting accepted from a user of the image forming apparatus.
In the above-described image forming apparatus, it is preferable that the optical adjustment member makes an amount of erasing light smaller in a case where the toner image formed on the surface of the photoreceptor after electrons are removed from the surface of the photoreceptor by the charge removal member is a toner image of a specific type of image than in a case where the toner image is not a toner image of a specific type of image, and the specific type of image includes at least any one of an image of an entire image forming region where the surface of the photoreceptor is exposed, an image of an image forming region where the surface of the photoreceptor is not exposed at all, and an image composed of only characters.
In the above image forming apparatus, it is preferable that the image forming apparatus further includes: a charging member for charging a surface of the photoreceptor; and a charging adjustment unit that adjusts a voltage applied to the charging unit based on the erasing light adjusted by the light adjustment unit.
In the above-described image forming apparatus, it is preferable that the charging adjustment member adjusts at least one of a peak-to-peak voltage value and a frequency of an alternating current component of the voltage applied to the charging member.
In the above image forming apparatus, it is preferable that the image forming apparatus further includes: the increase ratio setting means sets a ratio of increase of a value, which is an index of progress of deterioration of the photoreceptor, based on the amount of the erasing light adjusted by the light adjusting means.
According to another aspect of the present invention, there is provided a control program for an image forming apparatus, comprising: a photoreceptor; and a charge removing member that removes electrons from the surface of the photoreceptor by irradiating the surface of the photoreceptor with erasing light between the time of transfer of the toner image formed on the surface of the photoreceptor and the time of charging for forming the next toner image, wherein the control program causes the computer to execute a light adjusting step of adjusting the amount of erasing light based on at least one of information on the toner image formed on the surface of the photoreceptor after the electrons are removed from the surface of the photoreceptor by the charge removing member and a setting accepted from a user of the image forming apparatus.
According to the present invention, it is possible to provide an image forming apparatus and a control program for the image forming apparatus, which can suppress a decrease in the lifetime of the photoreceptor.
Drawings
Fig. 1 is a sectional view schematically showing the structure of an image forming apparatus 1 according to embodiment 1 of the present invention.
Fig. 2 is an enlarged view of the vicinity of the image forming unit 20A of fig. 1.
Fig. 3 is a diagram schematically showing a change in surface potential of the photoreceptor in the case where the erasing light is not irradiated.
Fig. 4 is a diagram schematically showing a change in surface potential of the photoreceptor when the erasing light is irradiated.
Fig. 5 is a diagram schematically showing a relationship between the amount of erasing light and the surface potential of the photoreceptor.
Fig. 6 is a graph showing the relationship between the erase light quantity and the potential difference between the unexposed portion and the exposed portion.
Fig. 7 is a diagram schematically showing the change in surface potential of the photoreceptor 22 in the case where a toner image of a solid image is formed on the surface of the photoreceptor 22 in a state where the potential difference between the unexposed portion and the exposed portion remains after transfer (no erasing light is irradiated) in embodiment 1 of the present invention.
Fig. 8 is a diagram schematically showing changes in the surface potential of the photoreceptor in a case where a toner image of a white image is formed on the surface of the photoreceptor in a state where the potential difference between the non-exposed portion and the exposed portion remains after transfer (a state where erasing light is not irradiated) in embodiment 1 of the present invention.
Fig. 9 is a flowchart showing the operation of image forming apparatus 1 according to embodiment 1 of the present invention.
Fig. 10 is a flowchart showing the operation of image forming apparatus 1 according to embodiment 2 of the present invention.
Description of the reference symbols
1. Image forming apparatus (an example of an image forming apparatus)
1a image forming apparatus main body
10. Paper conveying part
11. Paper feeding tray
12. Paper feeding roller
13. Positioning roller
14. Paper discharging roller
15. Paper discharging tray
20. Toner image forming part
20A image forming unit
21. Exposure portion
22. Photoreceptor (an example of photoreceptor)
23. Charged part (an example of charged member)
24. Developing part
25. Eraser unit (an example of a charge removing member)
26. Photoreceptor scraper
27. Primary transfer roller
28. Intermediate transfer roller
28a rotating roll
29. Secondary transfer roller
30. Fixing device
40. Control part (light adjusting component, charged adjusting component, and increasing ratio setting component)
41 CPU (Central processing Unit)
42 ROM (read only memory)
43 RAM (random access memory)
44. Counting part
50. Operation panel
D. Potential difference between D0 and D1 exposed portion and unexposed portion
E. E1, E2 Erase light quantity
ES erasing light
LT laser
MG fog residual
TR conveying path
Detailed Description
Embodiments of the present invention will be described below with reference to the drawings.
In the following embodiments, a case where the image forming apparatus is an MFP will be described. The image forming apparatus may be a facsimile apparatus, a copying machine, a printer, or the like, other than the MFP, and may be either monochrome or color.
[ 1 st embodiment ]
(Structure of image Forming apparatus)
Fig. 1 is a sectional view schematically showing a structure of an image forming apparatus 1 (an example of an image forming apparatus) according to embodiment 1 of the present invention. Fig. 2 is an enlarged view of the vicinity of the image forming unit 20A of fig. 1.
Referring to fig. 1 and 2, the image forming apparatus 1 according to the present embodiment is an MFP, and mainly includes a paper feeding unit 10, a toner image forming unit 20, a fixing device 30, a control unit 40 (an example of an optical adjustment member, a charging adjustment member, and an increase ratio setting member), and an operation panel 50.
The sheet conveying section 10 conveys a sheet along a conveying path (conveying direction) TR. The paper conveying unit 10 includes a paper feed tray 11, a paper feed roller 12, registration rollers 13, paper discharge rollers 14, and a paper discharge tray 15. The paper feed tray 11 accommodates paper for forming an image. The number of the sheet feed trays 11 may be plural. The paper feed roller 12 is provided between the paper feed tray 11 and the conveyance path TR. The registration roller 13 is provided on the more upstream side of the secondary transfer roller 29 in the conveying path TR. The discharge rollers 14 are provided at the most downstream portion of the conveying path TR. The paper discharge tray 15 is provided at the uppermost part of the image forming apparatus main body 1 a.
The toner image forming unit 20 combines images of four colors, Y (yellow), M (magenta), C (cyan), and K (black), in a so-called tandem manner, and forms a toner image on a sheet being conveyed. The toner image forming portion 20 includes an image forming unit 20A for each color YMCK, an exposure portion 21, a primary transfer roller 27 for each color YMCK, an intermediate transfer belt 28, and a secondary transfer roller 29.
The image forming units 20A of YMCK colors are disposed in order in the direction of rotation of the intermediate transfer belt 28 indicated by arrow β between the exposure section 21 and the intermediate transfer belt 28. The image forming unit 20A for each color YMCK includes a photoreceptor 22 (an example of a photoreceptor), a charging unit 23 (an example of a charging member), a developing unit 24, an eraser unit 25 (an example of a charge removing member), a photoreceptor blade 26, and the like. The photoconductor 22 is grounded and is rotationally driven in a direction indicated by an arrow α in fig. 1. Around the photoreceptor 22, a charging section 23, a developing section 24, an eraser section 25, and a photoreceptor blade 26 are provided in this order in the direction indicated by the arrow α.
The intermediate transfer belt 28 is provided above the image forming units 20A of YMCK colors. The intermediate transfer belt 28 is formed of an endless belt, and is stretched over a rotating roller 28 a. The intermediate transfer belt 28 is rotationally driven in a direction indicated by an arrow β in fig. 1. Each of the primary transfer rollers 27 for each color of YMCK faces each of the photoreceptors 22 with the intermediate transfer belt 28 interposed therebetween. The secondary transfer roller 29 is in contact with the intermediate transfer belt 28 in the conveying path TR. The photoreceptor 22 contacts the surface of the intermediate transfer belt 28.
The fixing device 30 holds the sheet on which the toner image is formed by the fixing nip portion, and conveys the sheet along the conveying path TR to fix the toner image to the sheet.
The control section 40 controls the entire image forming apparatus 1. Specifically, the control section 40 controls each of the voltage applied to the charging section 23 (charging output), the voltage applied to the developing roller of the developing section 24 (developing output), the voltage applied to the primary transfer roller 27 (primary transfer output), the amount of erasing light ES irradiated by the eraser section 25, and the output applied to the secondary transfer roller 29 (secondary transfer output). The control Unit 40 includes a CPU (Central Processing Unit) 41 that operates in accordance with a control program, a ROM (Read Only Memory) 42 that stores various information such as the control program, a RAM (Random Access Memory) 43 that temporarily stores data used by the CPU, and a counting Unit 44 that counts the cumulative number of rotations of the photoreceptor 22.
The operation panel 50 displays various information and accepts various operations.
The primary transfer output and the secondary transfer output are constant voltages of direct current. The charging output and the toner are of the same polarity, and the primary transfer bias and the secondary transfer bias and the charging output and the toner are of the opposite polarity. In the present embodiment, the polarities of the charging output, the developing output, and the toner are all negative, and the polarities of the primary transfer output and the secondary transfer output are positive.
The control unit 40 rotates the photoreceptor 22, and uniformly charges the surface of the photoreceptor 22 by the charging unit 23. The image forming apparatus 1 exposes the surface of the charged photoreceptor 22 with the laser light LT irradiated from the exposure section 21 in accordance with image information, and forms an electrostatic latent image serving as a base of a toner image on the surface of the photoreceptor 22.
Next, the control section 40 supplies toner from the developing section 24 to the photoreceptor 22 on which the electrostatic latent image is formed to develop the toner, and forms a toner image on the surface of the photoreceptor 22.
Next, the control section 40 uses the primary transfer roller 27 to electrostatically sequentially transfer the toner images formed on the surface of the photoreceptor 22 to the surface of the intermediate transfer belt 28 at the contact position of the photoreceptor 22 and the intermediate transfer belt 28 (primary transfer). In the case of a full-color image, the toner image transferred onto the surface of the intermediate transfer belt 28 is superimposed with respective colors each time it passes through each of the image forming units 20A, and finally a full-color toner image is formed on the surface of the intermediate transfer belt 28.
By the exposure and transfer, a potential difference is generated on the surface of the photoreceptor 22 after the transfer depending on the position. Therefore, the control section 40 irradiates the surface of the photoreceptor 22 after the primary transfer with the erasing light ES from the eraser section 25, thereby removing the electrons remaining after the primary transfer from the surface of the photoreceptor 22. This lowers the surface potential of the photoreceptor 22. Further, the control section 40 removes the toner remaining on the surface of the photoreceptor 22 without being transferred onto the intermediate transfer belt 28 by the photoreceptor blade 26. Subsequently, the control section 40 charges the surface of the photoconductor 22 for the next image formation.
Next, the control section 40 conveys the toner image formed on the surface of the intermediate transfer belt 28 to a position facing the secondary transfer roller 29 by the rotating roller 28 a.
On the other hand, the control unit 40 feeds the paper accommodated in the paper feed tray 11 one by the paper feed roller 12, and guides the paper between the intermediate transfer belt 28 and the secondary transfer roller 29 at a predetermined timing by the registration roller 13. Then, the control section 40 electrostatically transfers the toner image formed on the surface of the intermediate transfer belt 28 to the paper sheet by the secondary transfer roller 29.
The control unit 40 guides the paper sheet to which the toner image is transferred to the fixing device 30, and fixes the toner image on the paper sheet by the fixing device 30. Subsequently, the control section 40 discharges the sheet with the toner image fixed thereon onto the discharge tray 15 by the discharge roller 14.
Referring to fig. 2, attention is paid to the steps performed on the surface of the photoreceptor 22. Charging, exposure, development, and transfer are sequentially performed on the surface of the photoreceptor 22, and thereby the toner image formed on the surface of the photoreceptor 22 is primarily transferred to the intermediate transfer belt 28. After the transfer, the surface of the photoreceptor 22 is subjected to static elimination and residual toner removal, and then a toner image to be formed next is charged.
In the present specification, the level of the potential on the surface of the photoreceptor means the level of the absolute value of the potential on the surface of the photoreceptor.
(function of erasing light)
Next, the function of the erasing light irradiated to the surface of the photoreceptor will be described.
Fig. 3 is a diagram schematically showing a change in surface potential of the photoreceptor in the case where the erasing light is not irradiated.
Referring to fig. 3, for example, a potential of about-500V is applied to the surface of the photoreceptor during charging. Then, when the surface of the photoreceptor is exposed, the potential of the unexposed portion, which is an unexposed area on the surface of the photoreceptor, is maintained at about-500V, and the potential of the exposed portion, which is an exposed area on the surface of the photoreceptor, is lowered to about-50V. This is because electrons are removed from the surface of the photoreceptor by exposure.
As a result, as shown by the broken line in fig. 3 a, the potential difference between the non-exposed portion and the exposed portion before transfer (after development and before primary transfer) is increased. At the time of transfer, a transfer current flows between the photoreceptor and the primary transfer roller, and the potentials of the unexposed portion and the exposed portion are lowered. However, as shown by the solid line in fig. 3 a, the potential difference D between the non-exposed portion and the exposed portion is not uniform and remains after the transfer (after the primary transfer and before the exposure).
After the transfer, charging, exposure, development, and transfer for forming the next toner image are sequentially performed. When the erasing light is not irradiated, as shown in fig. 3 b, the potential difference D between the non-exposed portion and the exposed portion remains after charging (solid line in fig. 3 b) and after exposure (broken line in fig. 3 b) for forming the next toner image. As a result, when the next toner image to be formed is a half image (intermediate density image), the image is shaded (memory ghost) due to the potential difference D at a portion corresponding to the boundary between the portion that was not exposed previously (the portion that was not exposed when the previous toner image was formed) and the portion that was exposed previously (the portion that was exposed when the previous toner image was formed) in the next half image to be formed.
Fig. 4 is a diagram schematically showing a change in surface potential of the photoreceptor when the erasing light is irradiated.
Referring to fig. 4, when erasing light is irradiated, electrons remaining on the surface of the photoreceptor after transfer are removed by the erasing light, and the potential difference D between the unexposed portion and the exposed portion remaining after transfer is eliminated. The potential of the surface of the photoreceptor uniformly decreases to a certain level (thick line in fig. 4). Therefore, no shading occurs in the next image to be formed. Further, the surface of the photoreceptor may be irradiated with erasing light between the time of transfer of the toner image formed on the surface of the photoreceptor and the time of charging for forming the next toner image.
Fig. 5 is a diagram schematically showing the relationship between the amount of erasing light and the surface potential of the photoreceptor. Fig. 6 is a diagram showing a relationship between the amount of erasing light and the potential difference between the unexposed portion and the exposed portion.
Referring to fig. 5 and 6, the smaller the erasing light amount E, the smaller the amount of decrease in the surface potential of the photoconductor. When the erasing light amount E is zero (when erasing light is not irradiated), the potential difference between the non-exposed portion and the exposed portion is maintained as the potential difference D0 between the non-exposed portion and the exposed portion after transfer. When the erasing light amount E is small (E = E1> 0), the potential difference D1 between the non-exposed portion and the exposed portion is smaller than the potential difference D0 between the non-exposed portion and the exposed portion after the transfer by the irradiation of the erasing light (D1 < D0). When the erasing light amount E is sufficiently large (E = E2 > E1), the potential difference between the non-exposed portion and the exposed portion disappears.
(method of adjusting amount of erasing light)
In the present embodiment, the control unit 40 adjusts the amount of erasing light based on information of the toner image formed on the surface of the photoreceptor 22 after electrons are removed from the surface of the photoreceptor 22 by the erasing light irradiated by the eraser unit 25.
Specifically, the control section 40 makes the amount of erasing light in the case where the toner image formed on the surface of the photoreceptor 22 after the electrons are removed from the surface of the photoreceptor 22 by the erasing light irradiated by the eraser section 25 is a toner image of a specific kind of image smaller than the amount of erasing light in the case where the toner image is not a specific kind of image. The control unit 40 sets the erasing light amount to 0 or the erasing light amount E1 (fig. 5) when the toner image formed on the surface of the photoreceptor 22 after the electrons are removed by the erasing light irradiated from the eraser unit 25 is a toner image of a specific type of image, and sets the erasing light amount when the toner image is not a toner image of a specific type of image to a normal erasing light amount E2 (fig. 5).
The specific type of image is a solid image, a white image, a character image, or the like. The solid image is an image obtained by exposing the entire image forming region (region where a toner image can be formed) on the surface of the photoreceptor 22. The white image is an image in which the image forming region on the surface of the photoreceptor 22 is not exposed at all. The character image is an image composed of only characters.
Fig. 7 is a diagram schematically showing the change in surface potential of the photoreceptor 22 in the case where a toner image of a solid image is formed on the surface of the photoreceptor 22 in a state where the potential difference between the unexposed portion and the exposed portion remains after transfer (no erasing light is irradiated) in embodiment 1 of the present invention.
Referring to fig. 7, when the toner image formed on the surface of the photoreceptor 22 is a solid image, the entire image forming region of the surface of the photoreceptor 22 is exposed, and the entire image forming region becomes an exposed portion. As shown by the arrows in fig. 7, the potential of the surface of the photoconductor 22 uniformly decreases to a level depending on the light amount of the laser light LT (fig. 2) irradiated by the exposure section 21. Therefore, even if the potential difference D remains at a portion corresponding to the boundary between the portion that was not exposed and the portion that was exposed, the potential difference D disappears or decreases significantly during exposure of the toner image for forming a solid image.
In this way, when the toner image formed on the surface of the photoreceptor 22 after electrons are removed by the erasing light irradiated by the eraser portion 25 is a solid image, it is difficult to generate a shade (memory ghost) in a solid image to be formed next even if the amount of erasing light is reduced compared to normal.
Fig. 8 is a diagram schematically showing changes in the surface potential of the photoreceptor in a case where a toner image of a white image is formed on the surface of the photoreceptor in a state where the potential difference between the non-exposed portion and the exposed portion remains after transfer (a state where erasing light is not irradiated) in embodiment 1 of the present invention.
Referring to fig. 8, when the toner image formed on the surface of the photoreceptor is a white image, the image forming region on the surface of the photoreceptor is not exposed at all, and the entire image forming region becomes a non-exposed portion. Therefore, even after charging and exposure for forming a white image, the potential difference D remains at a portion corresponding to the boundary between the portion that was not previously exposed and the portion that was previously exposed.
However, in general, the potential difference between the developing roller of the developing section 24 and the exposed portion of the surface of the photoreceptor 22 is set sufficiently large so that unnecessary toner does not adhere to the surface of the photoreceptor 22 from the developing roller of the developing section 24 during development. The potential difference set between the developing roller of the developing section 24 and the exposed portion of the surface of the photoreceptor 22 is referred to as a fog margin MG.
The potential difference D is less than the fog margin MG. Therefore, regardless of whether the non-exposed portion or the exposed portion is previously formed, the potential of the non-exposed portion after the charging and the exposure for forming the white image is higher than the potential (developing potential) of the developing roller of the developing portion 24. At the time of development for forming a white image, the toner is difficult to adhere to the unexposed area.
In this way, when the toner image formed on the surface of the photoreceptor 22 after the electrons are removed by the erasing light irradiated from the eraser portion 25 is a white image, even if the amount of erasing light is reduced compared to the normal, the toner is less likely to adhere to the white image formed next, and the shading (memory ghost) is less likely to occur
Further, the character image is composed of a character portion having a high density corresponding to a solid image and a background portion having a zero density corresponding to a white image. Therefore, when the toner image formed on the surface of the photoreceptor 22 after the electrons are removed by the erasing light irradiated from the eraser portion 25 is a character image, it is difficult to generate a shade (memory ghost) on the character image formed next even if the amount of erasing light is reduced from the normal amount. In addition, the shading is not noticeable on the character image.
A relationship of "Q = CV" is established among the electrostatic capacity C of the photoreceptor, the voltage (surface potential of the photoreceptor) V applied to the photoreceptor, and the charge amount Q of the surface of the photoreceptor. In other words, when the surface potential of the photoreceptor before charging is high, the difference from the surface potential of the photoreceptor targeted at the time of charging is small, and thereby the necessary charge amount Q (the charge amount Q of electrons to be discharged) is also small. Therefore, the damage of the photoreceptor due to the discharge energy of the electrons is also reduced, and the surface of the photoreceptor is less likely to be abraded. In general, the occurrence of charging defects due to a decrease in film thickness is a factor that affects the life of the photoreceptor, and therefore, if the rate of decrease in film thickness on the surface of the photoreceptor is slowed, the life of the photoreceptor can be inhibited from decreasing.
When the surface of the photoreceptor 22 is not irradiated with erasing light after transfer, the surface potential of the photoreceptor 22 before charging becomes high. Therefore, by adjusting the erase light amount and reducing the erase light amount in a predetermined case as described above, the difference between the target surface potential of the photoreceptor 22 and the surface potential of the photoreceptor before charging can be reduced at the next charging, and damage to the photoreceptor 22 due to the discharge energy of electrons can be reduced. As a result, the decrease in image quality can be suppressed, and the life of the photoreceptor 22 can be suppressed from decreasing.
(charged output)
The control section 40 may adjust the voltage (charging output) applied to the charging section 23 based on the adjusted amount of erasing light. In particular, when the charging system of the charging section 23 is an AC charging system (when a voltage obtained by superimposing an AC voltage on a dc voltage is applied to the charging section 23), the control section 40 may adjust at least one of the peak-to-peak voltage value Vpp and the frequency of the AC component of the voltage applied to the charging section 23 based on the adjusted erase light quantity.
Generally, in the AC charging system, discharge and neutralization generated between a charging section and a photoreceptor are forcibly repeated by an alternating current component. Therefore, the uniformity of the surface potential of the photoreceptor after charging can be improved. On the other hand, in the AC charging system, since the number of discharges generated on the surface of the photoreceptor increases, abrasion of the surface of the photoreceptor tends to be promoted.
When the amount of erasing light is reduced by adjusting the erasing light by the above-described method, the surface potential of the photoreceptor 22 before charging becomes high. When the surface potential of the photoreceptor 22 before charging is high, the uniformity of the surface potential of the photoreceptor 22 after charging is ensured even if the peak-to-peak voltage value Vpp and the frequency of the alternating current component of the voltage applied to the charging unit 23 are small. Therefore, by reducing the peak-to-peak voltage value Vpp or the frequency of the alternating current component of the voltage applied to the charging section 23 based on the adjusted erasing light quantity, the number of times of discharge generated on the surface of the photoreceptor 22 can be reduced, and the life of the photoreceptor 22 can be suppressed from being reduced.
(count value)
The control section 40 may set the rate of increase of the cumulative number of rotations of the photosensitive body 22 counted by the counting section 44 based on the adjusted amount of erasing light.
Generally, when a value as an index of progress of deterioration of the photoreceptor such as the cumulative rotational speed exceeds a predetermined threshold value, it is determined that the photoreceptor has reached the end of its life. However, in the case of adjusting the erasing light and reducing the amount of erasing light by the above-described method, abrasion of the surface of the photosensitive body 22 is suppressed, and thus the life of the photosensitive body 22 is extended. As a result, even if it is determined that the photoreceptor 22 has reached the end of its life based on the count value of the counting portion 44, there may be a case where the photoreceptor 22 has not actually reached its end of life.
Therefore, when the erasing light amount is reduced by adjusting the erasing light by the above-described method, the control section 40 may set the rate of increase in the cumulative rotational number of the photosensitive member 22 counted by the counting section 44 to be smaller than the case where the erasing light amount is a normal amount. Accordingly, the count value of the counter 44 accurately reflects the actual state of the photoreceptor 22, and whether or not the photoreceptor 22 has reached the lifetime can be accurately determined based on the count value of the counter 44.
In the present embodiment, the case where the value as an index of the progress of the deterioration of the photoreceptor 22 is the cumulative rotational number of the photoreceptor 22 is shown. However, the value as an index of the progress of the deterioration of the photoreceptor 22 is not limited to this, and may be a rotation time or a travel distance of the photoreceptor 22, an application time of a charging output, the number of accumulated prints, or the like.
(flow chart)
Fig. 9 is a flowchart showing the operation of the image forming apparatus 1 according to embodiment 1 of the present invention.
Referring to fig. 9, after the toner image on the surface of the photoreceptor 22 is transferred, the control section 40 acquires image information of a toner image formed next on the surface of the photoreceptor 22 (S1), and determines whether or not the toner image formed next is a toner image of a solid image (S3).
In step S3, if it is determined that the toner image to be formed next is not the toner image of the solid image (no in S3), the control unit 40 determines whether or not the toner image to be formed next is the white image S5.
In step S5, if it is determined that the toner image to be formed next is not a white image (no in S5), the control unit 40 determines whether or not the toner image to be formed next is a toner image of a character image (S7).
If it is determined in step S3 that the toner image to be formed next is a solid image toner image (yes in S3), if it is determined in step S5 that the toner image to be formed next is a white image toner image (yes in S5), or if it is determined that the toner image to be formed next is a text image toner image (yes in S7), the control unit 40 reduces the amount of erasing light compared to normal (S9). Next, the control section 40 decreases the peak-to-peak voltage value Vpp or the frequency of the ac component of the voltage applied to the charging section 23 (S11), sets the rate of increase in the cumulative number of rotations of the photoreceptor 22 counted by the counting section 44 to "0.5" per rotation (S13), and ends the process.
In step S7, if it is determined that the toner image to be formed next is not the toner image of the character image (no in S7), the control unit 40 sets the erasing light amount to a normal value, and sets the peak-to-peak voltage value Vpp and the frequency of the ac component of the voltage applied to the charging unit 23 to normal values (S15). Next, the control section 40 sets the rate of increase in the cumulative number of rotations of the photosensitive body 22 counted by the counting section 44 to "1" per rotation (S17), and ends the processing.
In the present embodiment, the control unit 40 may adjust the amount of erasing light based on the setting of the user in addition to the information of the toner image formed on the surface of the photosensitive body 22 after the electrons are removed by the erasing light irradiated from the eraser unit 25.
(effects of the embodiment)
According to the present embodiment, by adjusting the amount of erasing light and reducing the amount of erasing light in a predetermined case, the difference between the target surface potential of the photoreceptor 22 and the surface potential of the photoreceptor before charging can be reduced at the next charging, and damage to the photoreceptor 22 due to the discharge energy of electrons can be reduced. As a result, the deterioration of the image quality can be suppressed, and the life of the photoreceptor 22 can be suppressed from decreasing.
In particular, when the toner image formed on the surface of the photoreceptor 22 after electrons are removed by the erasing light irradiated from the eraser portion 25 is a solid image, a white image, a character image, or the like, the decrease in image quality can be suppressed to a large extent by reducing the amount of erasing light.
[ 2 nd embodiment ]
There are cases where the user desires the life of the photoreceptor to be extended more than the quality of the image is improved. In view of this, the control unit 40 in the present embodiment adjusts the erasing light amount based on the setting accepted from the user of the image forming apparatus 1. For example, the control unit 40 displays an operation screen including options of "life priority" and "image quality priority" on the operation panel 50 in a predetermined case. The control unit 40 makes the erasing light amount in the case where the operation of selecting "life priority" is accepted on the operation panel 50 (in the case where the user setting of "life priority" is accepted) smaller than the erasing light amount in the case where the operation of selecting "image quality priority" is accepted on the operation panel 50 (in the case where the user setting of "image quality priority" is accepted).
Fig. 10 is a flowchart showing the operation of the image forming apparatus 1 according to embodiment 2 of the present invention.
Referring to fig. 10, after the toner image on the surface of the photosensitive member 22 is transferred, the control section 40 determines whether or not the user setting of "life priority" has been accepted (S21).
If it is determined in step S21 that the user setting of "life priority" has been accepted (yes in S21), the control unit 40 reduces the erase light amount compared to the normal light amount (S23). Next, the control section 40 decreases the peak-to-peak voltage value Vpp or the frequency of the ac component of the voltage applied to the charging section 23 (S25), sets the rate of increase in the cumulative number of rotations of the photoreceptor 22 counted by the counting section 44 to "0.5" per rotation (S27), and ends the process.
If it is determined in step S21 that the user setting of "life priority" has not been accepted (no in S21), the control unit 40 sets the erase light quantity to a normal value and sets the peak-to-peak voltage value Vpp and the frequency of the ac component of the voltage applied to the charging unit 23 to normal values (S29). Next, the control unit 40 sets the rate of increase in the cumulative number of rotations of the photosensitive body 22 counted by the counting unit 44 to "1" per rotation (S31), and ends the process.
The configuration and operations of the image forming apparatus 1 according to the present embodiment other than those described above are the same as those of the image forming apparatus according to embodiment 1, and therefore, the description thereof will not be repeated.
According to the present embodiment, when the amount of erasing light is reduced based on the setting accepted from the user, the difference between the target surface potential of the photoreceptor 22 and the surface potential of the photoreceptor before charging can be reduced at the next charging, and damage to the photoreceptor 22 due to the discharge energy of electrons can be reduced. As a result, the life of the photoreceptor 22 can be prevented from being reduced.
[ others ]
The control unit 40 may adjust the amount of erasing light based on at least one of information on the toner image formed on the surface of the photosensitive member 22 after the electrons are removed by the erasing light emitted from the eraser unit 25 and a setting accepted from the user of the image forming apparatus 1.
In addition to the color image forming apparatus including the intermediate transfer belt 28, the image forming apparatus 1 may be an image forming apparatus that directly transfers a toner image from the photoreceptor 22 to a sheet.
The above embodiments and modifications can be combined as appropriate.
The processing in the above-described embodiment may be performed by software, or may be performed by using a hardware circuit. Further, a program for executing the processing in the above-described embodiment may be provided, and the program may be recorded in a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, or a memory card and provided to a user. The program is executed by a computer such as a CPU. The program may be downloaded to the device via a communication line such as the internet.
The above-described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.
Claims (10)
1. An image forming apparatus includes:
a photoreceptor;
a charge removing member that removes electrons from the surface of the photoreceptor by irradiating erasing light to the surface of the photoreceptor between the time of transfer of a toner image formed on the surface of the photoreceptor and the time of charging for forming a next toner image; and
and an optical adjustment member that adjusts the amount of erasing light used for next electron removal based on at least one of information on a toner image formed on the surface of the photoreceptor after the electrons are removed from the surface of the photoreceptor by the charge removal member and a setting accepted from a user of the image forming apparatus.
2. The image forming apparatus as claimed in claim 1,
the light adjusting member makes the amount of erasing light smaller in the case where a toner image formed on the surface of the photoreceptor after electrons are removed from the surface of the photoreceptor by the charge removing member is a toner image of a specific type of image than in the case where the toner image is not a toner image of the specific type of image,
the specific type of image includes at least one of an image of the entire image forming region where the surface of the photoreceptor is exposed, an image of the image forming region where the surface of the photoreceptor is not exposed at all, and an image formed of only characters.
3. The image forming apparatus according to claim 1 or claim 2, further comprising:
a charging member that charges a surface of the photoreceptor; and
and a charging adjustment unit that adjusts a voltage applied to the charging unit based on the amount of the erasing light adjusted by the light adjustment unit.
4. The image forming apparatus as claimed in claim 3,
the charging adjustment unit adjusts at least one of a peak-to-peak voltage value and a frequency of an alternating current component of a voltage applied to the charging unit.
5. The image forming apparatus according to claim 1 or 2, further comprising:
and an increase ratio setting unit that sets a ratio of increase of a value that is an index of progress of deterioration of the photoreceptor, based on the amount of the erasing light adjusted by the light adjusting unit.
6. A computer-readable recording medium storing a control program for an image forming apparatus, the image forming apparatus comprising:
a photoreceptor; and
a charge removing member for removing electrons from the surface of the photoreceptor by irradiating erasing light to the surface of the photoreceptor between the time of transfer of a toner image formed on the surface of the photoreceptor and the time of charging for forming the next toner image,
the control program of the image forming apparatus causes a computer to execute a light adjusting step of adjusting an amount of the erasing light for next removal of electrons based on at least one of information of a toner image formed on the surface of the photosensitive body after the electrons are removed from the surface of the photosensitive body by the charge removing member and a setting accepted from a user of the image forming apparatus.
7. The computer-readable recording medium storing a control program of an image forming apparatus according to claim 6,
in the light adjustment step, the amount of erasing light in a case where a toner image formed on the surface of the photoreceptor after electrons are removed from the surface of the photoreceptor by the charge removing member is a toner image of a specific type of image is made smaller than the amount of erasing light in a case where the toner image is not a toner image of the specific type of image,
the specific type of image includes at least one of an image of the entire image forming region where the surface of the photoreceptor is exposed, an image of the image forming region where the surface of the photoreceptor is not exposed at all, and an image composed of only characters.
8. The computer-readable recording medium storing a control program of an image forming apparatus according to claim 6 or 7, the control program further comprising:
a charging step of charging a surface of the photoreceptor; and
a charging adjustment step of adjusting the voltage applied in the charging step based on the amount of the erasing light adjusted by the light adjustment step.
9. The computer-readable recording medium storing a control program of an image forming apparatus according to claim 8,
in the charging adjustment step, at least one of a peak-to-peak voltage value and a frequency of an alternating current component of the voltage applied in the charging step is adjusted.
10. The computer-readable recording medium storing a control program of an image forming apparatus according to claim 6 or 7, the control program of the image forming apparatus further comprising:
an increase rate setting step of setting a rate of increase of a value that is an index of a progress of deterioration of the photoconductor based on the amount of the erasing light adjusted in the light adjusting step.
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| JP2018220767A JP7188014B2 (en) | 2018-11-26 | 2018-11-26 | IMAGE FORMING APPARATUS AND IMAGE FORMING APPARATUS CONTROL PROGRAM |
| JP2018-220767 | 2018-11-26 |
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| CN111221230B true CN111221230B (en) | 2022-11-01 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09101687A (en) * | 1995-10-05 | 1997-04-15 | Minolta Co Ltd | Image forming device |
| US6026267A (en) * | 1997-12-05 | 2000-02-15 | Minolta Co., Ltd. | Image forming apparatus including a pre-transfer eraser |
| US6198892B1 (en) * | 1999-02-02 | 2001-03-06 | Minolta Co., Ltd. | Image forming apparatus using erase light |
| JP2009042738A (en) * | 2007-07-17 | 2009-02-26 | Canon Inc | Image forming apparatus |
| CN102221807A (en) * | 2010-04-13 | 2011-10-19 | 京瓷美达株式会社 | Image-forming apparatus |
| CN107315333A (en) * | 2016-04-27 | 2017-11-03 | 京瓷办公信息***株式会社 | Neutralizer and image processing system |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3502676B2 (en) * | 1994-12-20 | 2004-03-02 | 株式会社リコー | Transfer transfer device |
| JP2003076076A (en) | 2001-08-31 | 2003-03-14 | Canon Inc | Image forming device |
| JP4090404B2 (en) | 2003-08-04 | 2008-05-28 | シャープ株式会社 | Image forming apparatus |
| JP2007183520A (en) | 2006-01-10 | 2007-07-19 | Ricoh Co Ltd | Image forming apparatus |
| JP2010190968A (en) | 2009-02-16 | 2010-09-02 | Canon Inc | Image-forming device |
| JP6648501B2 (en) | 2015-05-25 | 2020-02-14 | 株式会社リコー | Image forming method and image forming apparatus |
| JP2019008040A (en) | 2017-06-22 | 2019-01-17 | 京セラドキュメントソリューションズ株式会社 | Image forming apparatus and image forming method |
-
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- 2018-11-26 JP JP2018220767A patent/JP7188014B2/en active Active
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09101687A (en) * | 1995-10-05 | 1997-04-15 | Minolta Co Ltd | Image forming device |
| US6026267A (en) * | 1997-12-05 | 2000-02-15 | Minolta Co., Ltd. | Image forming apparatus including a pre-transfer eraser |
| US6198892B1 (en) * | 1999-02-02 | 2001-03-06 | Minolta Co., Ltd. | Image forming apparatus using erase light |
| JP2009042738A (en) * | 2007-07-17 | 2009-02-26 | Canon Inc | Image forming apparatus |
| CN102221807A (en) * | 2010-04-13 | 2011-10-19 | 京瓷美达株式会社 | Image-forming apparatus |
| CN107315333A (en) * | 2016-04-27 | 2017-11-03 | 京瓷办公信息***株式会社 | Neutralizer and image processing system |
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| JP2020086135A (en) | 2020-06-04 |
| CN111221230A (en) | 2020-06-02 |
| JP7188014B2 (en) | 2022-12-13 |
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