JP2004138879A - Simultaneous double-sided image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simultaneous double-sided image forming apparatus that forms a high quality image with high processing efficiency. <P>SOLUTION: In a simultaneous double-sided image forming apparatus, a first image formed by image forming devices A, B, C, and D are transferred and held on a primary image carrier 20, and the first image is transferred and held on a secondary image carrier 30 in the primary transfer position. Subsequently, a second image separately formed by the image forming devices A, B, C, and D is transferred and held on the primary image carrier 20, and the second image and the first image are transferred in the primary transfer position and a secondary transfer position, respectively, to form the images on both the sides of a recording material. The apparatus has a P-sensor (density detection means)37 that detects the toner density of the image held on the secondary image carrier 30. Irradiating strength (image forming condition) of an exposure means 18 is determined based on a reflected-light voltage value (information) detected by the P-sensor 37. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, a first image formed by an image forming apparatus is transferred and carried on a primary image carrier, and after the first image is transferred to a secondary image carrier at a primary transfer position, the image is formed. The second image separately formed by the image device is transferred to and held on the primary image carrier, and the second image is transferred at the primary transfer position, and the first image is transferred at the secondary transfer position. The present invention relates to a simultaneous double-sided image forming apparatus such as a printer, a facsimile, a copying machine, and a multifunction machine for forming images on both sides of a recording medium. In particular, it relates to an electrophotographic simultaneous double-sided image forming apparatus.
[0002]
[Prior art]
As a conventional double-sided image forming apparatus, a first image formed by an image forming apparatus is transferred onto one surface of a recording medium, and then the recording medium is turned over by a reversing apparatus and re-printed on the image forming apparatus. In some cases, the supplied and separately formed second image is transferred to the other surface of the recording medium.
[0003]
However, in such a double-sided image forming apparatus, after transferring the first image to one surface of the recording medium, the reversing device reverses the front and back of the recording medium. And the processing efficiency is poor. Thus, the following simultaneous double-sided image forming apparatus capable of forming images on both sides of a recording medium almost simultaneously has been disclosed.
[0004]
[Patent Document 1]
JP 9-258518 A
In the simultaneous double-sided image forming apparatus, a first image is formed on one drum-shaped image carrier by four developing means of yellow, magenta, cyan, and black, and the first image is formed by a transfer means. After the transfer to the carrier, a second image is separately formed on the image carrier by the developing means. Then, the first image carried on the image carrier is transferred onto the surface of the recording medium conveyed by the medium carrying device, and the second image formed on the image carrier is transferred to the image carrier. To form an image on both sides of the recording medium.
[0006]
However, in such a simultaneous double-sided image forming apparatus, since the exposing means is provided inside the image carrier, there is a problem that the image carrier becomes large and the apparatus cannot be made compact. Therefore, the following simultaneous double-sided image forming apparatus is disclosed.
[0007]
[Patent Document 2]
JP 2000-293065 A
In this simultaneous double-sided image forming apparatus, toner images are formed on four image forming members by four developing means of yellow, magenta, cyan, and black, respectively, and the first image is transferred to the image bearing member by transferring means. After the transfer to form the first image, a toner image is separately formed on each image carrier. Then, the first image carried on the image carrier is transferred onto the surface of the recording medium transported by the medium transport device, and the four color toner images formed on the four image carriers are formed. The second image is formed directly on the back surface by direct transfer with the carrier, and the image is formed on both sides of the recording medium.
[0009]
[Problems to be solved by the invention]
However, in such a simultaneous two-sided image forming apparatus, since the four image forming members are brought into direct contact with the recording medium to form the second image, dust or paper dust adhering to the recording medium is not formed. There is a problem in that the toner adheres to the carrier and causes white spots or the like at the time of subsequent image formation, and the image quality deteriorates.
[0010]
Therefore, a first object of the present invention is to provide a simultaneous double-sided image forming apparatus capable of forming a high-quality image with high processing efficiency.
[0011]
A second object of the present invention is to obtain an image having an optimum toner density.
[0012]
A third object of the present invention is to provide a simultaneous double-sided image forming apparatus which is easy to maintain.
[0013]
A fourth object of the present invention is to provide a compact and inexpensive simultaneous double-sided image forming apparatus.
[0014]
[Means for Solving the Problems]
Therefore, according to the first aspect of the present invention, in order to achieve the first object, the first image formed by the image forming apparatus is transferred onto a primary image carrier and carried, and the first image is carried. Is transferred to a secondary image carrier at the primary transfer position and carried, and then a second image separately formed by the image forming apparatus is transferred to and carried on the primary image carrier, and the second image In a simultaneous double-sided image forming apparatus for forming an image on both sides of a recording medium by transferring an image at the primary transfer position and transferring the first image at a secondary transfer position, the image is carried by the secondary image carrier. The image forming apparatus further includes a density detecting unit that detects a toner density of the transferred image, and determines an image forming condition of the image forming apparatus based on information detected by the density detecting unit.
[0015]
According to a second aspect of the present invention, in the simultaneous double-sided image forming apparatus according to the first aspect, the image forming condition is an irradiation intensity of an exposure unit of the image forming apparatus. It is characterized by the following.
[0016]
According to a third aspect of the present invention, in the simultaneous double-sided image forming apparatus according to the first aspect, the image forming condition is a voltage applied to a charging unit of the image forming apparatus. There is a feature.
[0017]
According to a fourth aspect of the present invention, there is provided a simultaneous double-sided image forming apparatus according to the first aspect, wherein the image forming condition is applied to a developing unit of the image forming apparatus. It is a voltage.
[0018]
According to a fifth aspect of the present invention, in order to achieve the third object, in the simultaneous plane image forming apparatus according to any one of the first to fourth aspects, the image forming apparatus main body is connected to the primary image carrier. And a sub-body part provided with the secondary image carrier, the sub-body part can be opened and closed with respect to the main part, and the main body part is provided with the density detecting means. And
[0019]
According to a sixth aspect of the present invention, in order to achieve the third object, in the simultaneous double-sided image forming apparatus according to the fifth aspect, a secondary transfer for transferring the first image to the recording medium is performed. A means is provided in the main body.
[0020]
According to a seventh aspect of the present invention, in order to achieve the fourth object, in the simultaneous double-sided image forming apparatus according to any one of the first to sixth aspects, the recording medium is formed by using the density detecting means. The conveyance jam is detected by the control unit.
BEST MODE FOR CARRYING OUT THE INVENTION
[0021]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an overall schematic configuration of a simultaneous double-sided image forming printer which is an example of a simultaneous double-sided image forming apparatus of the present invention.
[0022]
The illustrated simultaneous double-sided image forming printer is capable of forming images almost simultaneously on the front and back surfaces of a recording medium P such as a sheet of paper and an OHP film. As shown in FIG. , Four image forming apparatuses A, B, C, and D, a primary image carrier E, a secondary image carrier F, a medium transport device G, a fixing device H, a discharge stack device I, a toner replenishing device J, and the like. .
[0023]
The four image forming apparatuses A, B, C, and D form different single-color images using yellow, magenta, cyan, and black color toners, respectively, and each have a drum-shaped image forming support rotatably supported. The image forming body 12 is provided in a tandem manner, and a charging unit 13, a developing unit 14, an image forming and transferring unit 15, an image forming cleaning unit 16, an image forming and removing unit 17, and a backing roller 19 are provided around the respective image forming units 12. Is placed. Under the image forming apparatuses A, B, C, and D, a common exposure unit 18 that separately exposes the image forming carrier 12 is provided.
[0024]
The image carrier 12 is a photoconductor in which a layer of an organic semiconductor, which is a photoconductive substance, is provided on the surface of an aluminum cylinder having a diameter of about 20 to 100 mm. In this example, a drum shape is used, but a belt shape may be used.
[0025]
The exposure unit 18 irradiates light from an LD light source (not shown) toward the surface of the image carrier 12 with an optical component (not shown) by a known laser method, and scans the surface of the image carrier 12. To write to it. In this example, a laser method is used, but an exposure method using an LED array and an imaging component may be adopted.
[0026]
The primary image carrier E transfers and carries the images formed by the image producing devices A, B, C, and D, respectively. It is brought into contact with the image carrier 12 and is passed between each image carrier 12 and each corresponding image transfer device 15 and is wrapped around two primary rollers 21 and 22, and the primary cleaning device 24 and the primary transfer device are surrounded therearound. 25 are arranged.
[0027]
The primary image carrier 20 is a belt made of a resin film or rubber having a thickness of 50 μm to 500 μm, and has a resistance value capable of transferring toner from each image carrier 12.
[0028]
The secondary image carrier F is for transferring the image carried by the primary image carrier E by primary transfer and carrying the image. The belt-shaped secondary image carrier 30 is transferred to the primary image carrier 20 by the backing roller 32. A predetermined transfer nip is formed between the transfer roller and the transfer roller, and the transfer roller is wound around three secondary rollers 31, 33, and 34 and a backing roller 32 between the primary image carrier 20 and the primary transfer means 25. , A secondary cleaning unit 35, a secondary transfer unit 36, and the like.
[0029]
Like the primary image carrier 20, the secondary image carrier 30 is a resin film or rubber-based belt having a thickness of 50 μm to 600 μm, and has a resistance value at which toner can be transferred from the primary image carrier 20. Have.
[0030]
The medium conveying device G conveys the recording medium P through a medium conveying path extending from the lower side to the upper side in the figure by passing between the primary image carrier E and the secondary image carrier F, and is provided in two upper and lower stages. And a supply roller 41 for sequentially feeding the recording media P one by one from above from each medium storage container 40, and a medium guide for guiding the sent recording media P. 42, a registration roller 43 for abutting and stopping the leading end of the recording medium P guided and conveyed by the medium guide 42, a discharge guide 44 for guiding the recording medium P after image fixing, and a guide for the discharge guide 44. And a discharge roller 45 for discharging the recording medium P conveyed in the direction of arrow a.
[0031]
The fixing device H fixes a transfer image transferred from the primary image bearing device E and the secondary image bearing device F to the recording medium P, and includes a pair of heating rollers 47.
[0032]
The discharge stack device I is for stacking the recording medium P after image fixing by the fixing device H, and includes a stack section 50 formed on the image forming apparatus main body 10.
[0033]
The toner replenishing device J is for replenishing each of the image forming devices A, B, C, and D with new toner using a powder pump or the like, and includes toner cartridges 53 for each color.
[0034]
When a color image is formed on both sides of the recording medium P by the simultaneous double-sided image forming printer, one of the image carrier 12 and one of the primary rollers 21 and 22 is used based on a print signal from a host (not shown). , One of the secondary rollers 31, 33, and 34, the supply roller 41, and the like are rotated with a timing.
[0035]
In each of the image forming apparatuses A, B, C, and D, as each image forming carrier 12 rotates clockwise in FIG. Writing is performed with the individual writing light from 18 to form a latent image for each color, and a toner for each color is adhered by each developing means 14 to form a toner image for each color on each image carrier 12. . In the illustrated example, the polarity of the toner on the image carrier 12 is negative at this time.
[0036]
In the primary image carrier E, one of the primary rollers 21 and 22 is rotated and the other roller is driven to rotate, and the primary image carrier 20 is rotated counterclockwise in the figure in synchronization with the image carrier 12. The image transfer unit 15 conveys the primary image carrier 20 and transfers the images on the image carrier 12 sequentially by applying a positive charge to each of the image transfer units 15, and superimposes four colors to form a first full-color image ( (First image).
[0037]
After the image transfer, the image forming carriers 12 of each of the image forming apparatuses A, B, C, and D remove the residual toner by the image forming cleaning unit 16 and remove the charge by the image forming and removing unit 17. Thereafter, each of the charging means 13 is charged again, writing is performed by the exposure means 18, development is performed by each of the developing means 14, and a toner image of each color is formed again on each image forming carrier 12.
[0038]
In the secondary image carrier F, one of the secondary rollers 31, 33, and 34 is rotated and the other roller is driven to rotate, so that the secondary image carrier 30 is synchronized with the primary image carrier 20 in the figure. The paper is rotated clockwise, and the primary transfer unit 25 gives a positive charge to the secondary image carrier 30 to transfer the image on the primary image carrier 20. At this time, the secondary cleaning unit 35 is in a non-cleaning state in which the secondary cleaning unit 35 is rotated about a support shaft (not shown) and separated from the secondary image carrier 30.
[0039]
After the image transfer, the primary image carrier 20 of the primary image carrier E removes residual toner by the primary cleaning unit 24. After that, the images on the image carrier 12 are sequentially transferred to the primary image carrier 20 again by the respective image transfer means 15 to form a second full-color image (second image) in which four colors are superimposed. I do.
[0040]
After the image transfer, the image forming carriers 12 of the respective image forming apparatuses A, B, C, and D remove the residual toner by the image forming cleaning unit 16 and remove the charge by the image forming and discharging unit 17 to perform the next image forming cycle. Prepare for.
[0041]
On the other hand, in the medium transporting device G, one of the supply rollers 41 is selectively rotated as appropriate to feed out the recording medium P in the medium storage container 40, and guided by the medium guide 42 so that the leading end abuts between the registration rollers 43. Then, the registration roller 43 is rotated in synchronization with the first full-color image and the second full-color image described above, and is sent to a primary transfer position between the primary image carrier 20 and the secondary image carrier 30.
[0042]
First, a positive charge is applied to the surface of the recording medium P by the primary transfer means 25 at the primary transfer position to transfer the second full-color image on the primary image carrier 20, and then the recording medium P is slightly moved upward. The secondary transfer unit 36 applies a positive charge to the back surface at the secondary transfer position where the first full-color image has been conveyed to transfer the first full-color image on the secondary image carrier 30. Thereafter, the recording medium P on which the image has been transferred to the front and back surfaces is guided to the fixing device H, and heat and pressure are applied through a pair of heating rollers 47 to fix the transferred images on both surfaces. At 45, the sheet is discharged out of the image forming apparatus main body 10, and is stacked face down on the stack section 50 of the discharge stack apparatus I with its surface facing down.
[0043]
Therefore, the second page is formed first as a first full-color image, then the first page is formed later as a second full-color image, and the subsequent pages are similarly formed first to form a recording medium P When the image is transferred to the back side, the previous page is formed later, transferred to the front side, and output face down, the recording medium P can be arranged in the page order on the stack unit 50.
[0044]
At this time, using a known image processing technique, the second full-color image on the primary image carrier 20 is a normal image on the image carrier 12 and the first full-color image on the secondary image carrier 30. Needs to be a reverse image, ie, a mirror image, on the image carrier 12.
[0045]
After the image transfer, the primary image carrier 20 of the primary image carrier E removes the residual toner remaining on the primary image carrier 20 after the image transfer by the primary cleaning unit 24. The secondary image carrier 30 of the secondary image carrier F rotates the secondary cleaning unit 35 about the support shaft to be in a cleaning state, and the secondary cleaning unit 35 causes the residual toner on the secondary image carrier 30 to be in a cleaning state. To prepare for the next image carrying.
[0046]
When the toner in each developing unit 14 is used up, the toner of the same color is supplied from the corresponding toner cartridge 53 of the toner supply device J by a powder pump or the like.
[0047]
When the conveyance of the recording medium P is hindered by the jam, the sub-body N is opened in the direction of the arrow d around the support shaft 55, and the medium conveyance path is opened to perform the jam processing.
[0048]
When a full-color image is formed on one side of the recording medium P by the simultaneous double-sided image forming printer, the image formed on each of the image forming units 12 of the image forming units A, B, C, and D is copied to the primary image forming unit E. After the image is transferred to the primary image carrier 20, the image is sequentially transferred directly to one side of the recording medium P conveyed by the medium conveying device G without being transferred to the secondary image carrier 30 of the secondary image carrier F. To do it. Then, the transferred image is fixed by the fixing device H, and is discharged face-down to the discharge stack device I in a page order.
[0049]
Further, when a two-color image or a monochrome image is formed on the recording medium P by the illustrated printer, the image is formed by using an image forming apparatus of a corresponding color among the four image forming apparatuses A, B, C, and D. Then, the image is transferred to the recording medium P via the primary image carrier 20 of the primary image carrier E and the secondary image carrier 30 of the secondary image carrier F.
[0050]
In the simultaneous double-sided image forming printer of this example, an image forming apparatus main body 10 includes a main body M and a sub body N, and the main body M includes image forming apparatuses A, B, C, D, and a primary image holding device. The apparatus includes an apparatus E, a fixing apparatus H, a discharge stack apparatus I, a toner replenishing apparatus J, and the like. On the other hand, the sub-body N is provided with a secondary image holding device F, and the sub-body N is provided so as to be openable and closable with respect to the main body M.
[0051]
The main transfer section 36 includes a secondary transfer section 36 and a P sensor (density detection section) 37. More specifically, the P sensor 37 is an optical detector including a light emitting unit using an LED and a light receiving unit including a light receiving element, and detects the toner density of an image transferred and carried on the secondary image carrier 30. The information is fed back to a control unit (not shown) for controlling the image forming apparatuses A, B, C, and D. The information is slightly above the secondary transfer means 36 and the P sensor 37 and the secondary image. The recording medium P is provided so as to pass between the carrier 30. The control unit controls the exposure unit, which is an image forming condition for adjusting the amount of toner adhered from the image forming apparatuses A, B, C, and D onto the primary image carrier 20 based on the transmitted information. The irradiation intensity of 18 is controlled.
[0052]
Next, a method of controlling the amount of toner attached to the image forming carrier 12 will be described below. Prior to the control of the toner adhesion amount, a method of adjusting the light emission amount from the light emitting unit of the P sensor 37 to an appropriate value to correct the sensitivity of the P sensor 37 will be described. In the method of correcting the sensitivity of the P sensor 37, the reflectance changes due to the deterioration of the secondary image carrier 30 with time, and dust such as toner adheres to the P sensor 37, and the P sensor 37 becomes dirty. Even if light is emitted from the unit, the amount of reflected light received by the light receiving unit changes, so that the sensitivity of the P sensor 37 is corrected.
[0053]
As shown in FIG. 3, in order to measure the surface density of the secondary image carrier 30, while the secondary image carrier 30 is being conveyed in a state where no image is carried (S1), the light emitting portion of the P sensor 37 is turned on. The light is emitted at a predetermined reference light amount and is irradiated onto the secondary image carrier 30 (S2).
[0054]
Next, after the reflected light from the secondary image carrier 30 is received by the light receiving element of the light receiving unit, the voltage is converted. At this time, since no image is carried on the secondary image carrier 30, the amount of reflected light becomes the maximum amount as compared with the case where the image is carried, and the converted reflected light voltage value also becomes the maximum value. Since it changes due to the above-described cause, the light emission voltage value of the LED of the P sensor 37 is adjusted so that the reflected light voltage value Vmax with respect to the preset reference light amount (S3). When the number of times of adjustment is the first time, the process proceeds to S4 after passing through this step.
[0055]
Then, it is determined whether or not the number of adjustments N is less than a predetermined value of 10 (S4). If the number of adjustments is less than 10, the process proceeds to S5, and the light emitting unit of the P sensor 37 is adjusted with the adjusted light emitting voltage value. , And the light reflected from the secondary image carrier 30 is received by the light receiving unit to be converted into a voltage. Next, in S6, it is determined whether the reflected light voltage value V is the reflected light voltage value Vmax with respect to the reference light amount.
[0056]
When the reflected light voltage value V is the reflected light voltage value Vmax with respect to the reference light amount, the image forming condition for controlling the toner adhesion amount, which is the density adjustment in the image forming process, is set.
[0057]
On the other hand, if the reflected light voltage value V is not the reflected light voltage value Vmax with respect to the reference light amount in S6, the difference between the reflected light voltage value Vmax and the reflected light voltage value V with respect to the reference light amount is calculated in S7 ( S7) The controller adjusts the light emission voltage value from the P sensor 37 so that the reflected light voltage value Vmax with respect to the reference light amount is obtained (S3).
[0058]
In S4, when the number of adjustments N becomes 10 times, the process proceeds to S8, where it is determined that there is an abnormality in LED light emission of the light emitting unit or an abnormality of the surface of the secondary image carrier 30, and the fact is notified.
[0059]
Next, a method of controlling the toner adhesion amount will be described with reference to FIG. After adjusting the amount of light emitted from the light emitting portion of the P sensor 37 to an appropriate value, the secondary image carrier 30 is transported (S11), and the image forming devices A, B, C, and D are exposed to the image carrier 12. The irradiation intensity (image forming condition) is adjusted by the means 18 (S12). If the number of adjustments is the first time, the process goes through this step and proceeds to S13.
[0060]
Then, in S13, it is determined whether the number of adjustments N is less than 10 times. If the number of adjustments N is less than 10, the process proceeds to S14, where the image forming devices A, B, C, and D form the toner patches of the maximum density and the halftone toner patches for each color, and the above-described procedure. Is transferred to the secondary image carrier 30 via the primary image carrier 20.
[0061]
The LED light is emitted from the light emitting unit of the P sensor 37 toward each toner patch, and the reflected light is received by the light receiving unit (S15), the voltage is converted by the light receiving element, and the reflected light voltage value (information) (S16). At this time, since the amount of reflected light scattered and reaches the light receiving portion changes depending on the toner density of the toner patch, it is determined whether the reflected light voltage value conforms to a predetermined density characteristic (S17). Then, the control of the toner adhesion amount ends.
[0062]
On the other hand, if the reflected light voltage value does not conform to the predetermined density characteristic, the process proceeds to S18, where the difference between the reflected light voltage value and the predetermined density characteristic is calculated, and in S12, the image forming apparatuses A, B, and C are calculated. , D from the exposure means 18 to the image carrier 12 is adjusted.
[0063]
In S13, when the number of adjustments N has reached 10 times, the process proceeds to S19, where it is determined that there is an abnormality in the light emission of the LED or an abnormality in the secondary image carrier 30, and that is notified.
[0064]
In the above-described method of controlling the amount of toner adhesion, the intensity of irradiation from the exposure unit 18 to the image forming carrier 12 of each of the image forming apparatuses A, B, C, and D can be adjusted among the image forming conditions, and the density detection is performed. Although the irradiation intensity of the exposure unit 18 is determined based on the information detected by the P sensor 37 as a unit, the present invention is not limited to this, and the charging unit 13 of the image forming apparatuses A, B, C, and D is used. Or the developing bias voltage applied to the developing means 14 of the image forming apparatus is adjustable, and based on the information detected by the P sensor 37 as the density detecting means, the image forming apparatuses A, B, C, The voltage applied to the charging means 13 of D or the developing bias voltage applied to the developing means 14 of the image forming apparatus may be adjustable.
[0065]
Further, a function of detecting the conveyance jam of the recording medium P using the P sensor 37 of the above example may be added. In this case, when the P sensor 37 detects the presence of the recording medium P, the reflected light voltage value falls within a certain range, and if this value continues for a certain period of time, the control unit determines that a conveyance jam has occurred.
[0066]
Further, in the above-described example, the primary image carrier 20 and the secondary image carrier 30 are coated with a low surface energy on the surface layer, the volume resistivity of the entire belt is 10E6 to 10E12 Ω · cm, and the surface resistivity is 10E5. It is suitable when the value is 10E12Ω / □. In addition, it is more preferable that the belt of the secondary image carrier 30 is formed of polyimide or polyamide.
[0067]
In the above-described example, the primary image carrier 20 and the secondary image carrier 30 are both belt-shaped. However, the present invention is not limited to this. For example, a drum-shaped image carrier may be used. May be.
[0068]
In the simultaneous double-sided image forming printer of the above-described example, in FIG. 1, a cover 50a is provided on the stack section 50 of the sheet discharging stack apparatus I so as to be openable and closable about a fulcrum 50b, and the cover 50a is opened to supply toner. The toner cartridge 53 of the apparatus J can be easily replaced. Further, a heat insulating member W is provided between the toner replenishing device J and the fixing device H to prevent the toner cartridge 53 from repeatedly melting and solidifying due to the heat of the fixing device H, thereby preventing the toner quality from deteriorating. it can. Examples of the heat insulating member W include a resin, a planted resin, or a material obtained by laminating these materials so as to have an air layer. Further, by providing the fan 60 in the image forming apparatus main body 10, even if an air path is formed to take in outside air to cool the fixing device H, the heat insulating effect of the toner replenishing device J can be obtained.
[0069]
Further, if the secondary image carrier 30 provided in the sub-body portion N and the secondary rollers 31, 33, 34, etc. are configured as one unit, it is easy to replace the secondary image carrier 30 due to deterioration thereof. Can be taken out.
[0070]
Further, in the above-described example, the simultaneous double-sided image forming printer has been described as an example of the simultaneous double-sided image forming apparatus. However, the present invention is not limited to this, and the facsimile, the copying machine, a multifunction machine thereof, and the like. Can be applied to the simultaneous double-sided image forming apparatus.
[0071]
Further, among these simultaneous double-sided image forming apparatuses, the present invention can be applied to any of monochrome, two-color, and full-color simultaneous double-sided image forming apparatuses.
[0072]
【The invention's effect】
As described above, according to the first aspect of the invention, the first image formed by the image forming apparatus is transferred and carried on the primary image carrier, and the first image is transferred at the primary transfer position. After being transferred and carried on the secondary image carrier, the second image separately formed by the image forming device is transferred and carried on the primary image carrier, and the second image is transferred to the primary transfer position at the primary transfer position. Since one image is transferred at the secondary transfer position to form an image on both sides of the recording medium, images can be formed on both sides of the recording medium almost simultaneously. In addition, since the transfer of the image to the recording medium is performed by the primary image carrier and the secondary image carrier and is not directly performed by the image forming device, dust and paper dust adhered to the recording medium adhere to the image forming device. Therefore, white spots and the like do not occur during subsequent image formation. Therefore, it is possible to provide a simultaneous double-sided image forming apparatus capable of forming a high-quality image with high processing efficiency.
[0073]
Further, the image forming apparatus further includes density detecting means for detecting the toner density of the transferred image carried by the secondary image carrier, and determines the image forming conditions of the image forming apparatus based on the information detected by the density detecting means. It is possible to detect the toner density of the image on the secondary image carrier carrying the image immediately before transfer to the medium, and to obtain an image with the optimal toner density.
[0074]
According to the second aspect of the present invention, since the image forming condition is the irradiation intensity of the exposure unit of the image forming apparatus, an image having an optimal toner density can be obtained by adjusting the irradiation intensity.
[0075]
According to the third aspect of the present invention, since the image forming condition is the voltage applied to the charging unit of the image forming apparatus, the image having the optimum toner density is adjusted by adjusting the voltage applied to the charging unit of the image forming apparatus. Can be obtained.
[0076]
According to the fourth aspect of the invention, since the image forming condition is the developing bias voltage applied to the developing unit of the image forming apparatus, the optimum developing bias voltage applied to the developing unit of the image forming apparatus is adjusted. An image having a toner density can be obtained.
[0077]
According to the fifth aspect of the invention, the main body includes the main body and the sub-body, and the main body includes the primary image carrier and the density detecting unit, while the sub-body includes the secondary image carrier, Since the body can be opened and closed with respect to the main body, the maintenance of the density detecting means can be performed by opening the sub-body, and a simultaneous double-sided image forming apparatus which is easy to maintain can be provided.
[0078]
According to the sixth aspect of the present invention, the secondary transfer unit for transferring the first image to the recording medium is provided in the main unit. Therefore, when the secondary transfer unit is maintained, the maintenance is performed by opening the sub-body unit. It is possible to provide a simultaneous double-sided image forming apparatus which can be easily maintained.
[0079]
According to the seventh aspect of the invention, since the jam of the recording medium is detected by the density detecting means, it is not necessary to separately provide a device for detecting the jam, and a compact and inexpensive simultaneous double-sided image forming apparatus can be provided. .
[Brief description of the drawings]
FIG. 1 is an overall schematic configuration diagram of a simultaneous double-sided image forming printer which is an example of a simultaneous double-sided image forming apparatus of the present invention.
FIG. 2 is a view showing a state where the sub-body portion is opened with respect to a main body portion.
FIG. 3 is a flowchart illustrating a method of controlling a light emission voltage value by a P sensor.
FIG. 4 is a flowchart illustrating a method of setting an image forming condition by a P sensor.
[Explanation of symbols]
13 charging means 14 developing means 18 exposing means 20 primary image carrier 30 secondary image carrier 36 secondary transfer means 37 P sensor (density detecting means)
A, B, C, D Imaging device K1 First full-color image (first image)
K2 Second full-color image (second image)
M Main body part N Subbody part P Recording medium Tr1 Primary transfer position Tr2 Secondary transfer position

Claims (7)

The first image formed by the image forming device is transferred and carried on the primary image carrier, and the first image is transferred and carried on the secondary image carrier at the primary transfer position, and then the image is formed. A second image separately formed by an image device is transferred to and held on the primary image carrier, and the second image is transferred at the primary transfer position, and the first image is transferred at the secondary transfer position. In a simultaneous double-sided image forming apparatus for transferring and forming images on both sides of a recording medium,
Density detecting means for detecting a toner density of a transferred image carried by the secondary image carrier, and image forming conditions of the image forming apparatus are determined based on information detected by the density detecting means. A simultaneous double-sided image forming apparatus. 2. The simultaneous double-sided image forming apparatus according to claim 1, wherein the image forming condition is an irradiation intensity of an exposure unit of the image forming apparatus. 2. The simultaneous double-sided image forming apparatus according to claim 1, wherein the image forming condition is a voltage applied to a charging unit of the image forming apparatus. 2. The simultaneous double-sided image forming apparatus according to claim 1, wherein the image forming condition is a developing bias voltage applied to a developing unit of the image forming apparatus. The image forming apparatus main body includes a main body including the primary image carrier and a sub-body including the secondary image carrier, and the sub-body can be freely opened and closed with respect to the main body. The simultaneous image forming apparatus according to any one of claims 1 to 4, wherein the unit includes the density detecting unit. 6. The simultaneous double-sided image forming apparatus according to claim 5, wherein a secondary transfer unit for transferring the first image onto the recording medium is provided in the main body. The simultaneous double-sided image forming apparatus according to any one of claims 1 to 6, wherein the control unit detects a conveyance jam of the recording medium using the density detection unit.

Images