JPH02158761A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the life of a photosensitive body from shortening by stopping the driving of the photosensitive body for a period from forming a developed image on the 1st image plane of a transfer sheet till forming the developed image on a 2nd image plane. CONSTITUTION:After finishing writing the image on the 1st image plane by a laser beam, at first, an electrostatic charger 2A is turned off and the bias of fixing rollers 14 and 15 is turned off at a prescribed timing, and after turning the electrostatic charger 2A off, a pre-exposure device 2B is turned off when the photosensitive drum 1 rotates at nearly once, a main motor continues to rotate and the driving of the photosensitive drum 1 is allowed to be stopped by cutting the transmission from the main motor by the use of a clutch. And when the transfer sheet is allowed to perform a switchback once and the 1st image plane is replaced with the 2nd image plane, the clutch is turned on again, so that the photosensitive drum 1 starts rotating and at the nearly same time, the electrostatic charger 2A is turned on. Thus, the unnecessary driving of the photosensitive body 1 can be reduced and the life of it can be prevented from shortening.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is an image forming apparatus such as a copying machine or a printer that applies electrophotography, and has a double-sided printing function that allows printing on both sides of a transfer sheet on which an image is transferred. The present invention relates to an image forming apparatus having an image forming apparatus, and particularly relates to control of a photoreceptor, a fixing means, a cleaning means, etc. inside the apparatus.

(Prior Art) A conventional example of a laser beam printer, which is one of image forming apparatuses using conventional electrophotography, and which has the above-mentioned double-sided printing function is shown in FIG. Around the photosensitive drum 1, there is a charger 2A for uniformly charging the surface of the photosensitive drum 1, which develops an electrostatic latent image formed by laser scanning the surface charged in the negative direction. a developing device 3 for transferring the developed image, a transfer roller 4 for transferring the developed image onto a transfer paper serving as a transfer sheet, a cleaner 5 serving as a cleaning means for cleaning the surface of the photosensitive drum 1 after the transfer, and the laser. Laser scanning optical system for scanning 6. A reflecting mirror 7 is provided to reflect the scanned laser toward the photosensitive drum.

A pre-exposure device 2B is provided upstream of the charger 2A to erase the history of the previous electrostatic latent image formation.

Transfer paper, which is a transfer sheet, is loaded and stored inside a cassette 8, and a half-moon-shaped pick-up roller 9
The paper is fed by The fed transfer paper is transferred to paper feed roller 1.
0.11, it is sent to the registration roller 12.13 and synchronized with the image writing of the laser scanning optical system 6. After the surface of the photoreceptor l is uniformly charged by the charger zA, it is exposed to light by the laser scanning optical system 6 to form an electrostatic latent image on the surface, and then the latent image is visualized by the developer 3. be done. This developed image is transferred onto a transfer paper by a transfer roller 4, and the residual toner remaining after the transfer is collected by a cleaner 5.

The transfer paper with the toner image transferred to its surface is transferred to the heat fixing roller 1.
The toner is fixed on the surface of the transfer paper by step 4.15 and sent by fixing exit roller 16.17. When double-sided printing is performed here, the transfer paper is moved by the flapper 18A.
First, it is sent out downward (toward the conveyance guide 19 side), and thereafter the conveyance rollers 21, 22, 23, 24. After passing through the half-moon roller 26 and being partially discharged to the outside of the main body 31, it is switched back by the half-moon roller 25 and sent to the flapper 18B.
The paper is sent to two-sided paper feed rollers 27 and 28 by the following steps. The flapper 18B is a guide for feeding the paper upward during switchpacking.

The transfer paper, which has been turned upside down in this manner, is fed again to the registration rollers 12 and 13, and printing on the second side is performed in synchronization with the image writing by the laser scanning optical system 6. After the transfer paper carrying the image on the second side is fixed by the fixing n-ra 14.15,
The transfer paper is sent out by the fixing exit rollers 16 and 17, but this time, the flapper 18A is rotated in the direction of the arrow, and the transfer paper is sent out upward (toward the conveyance guide 20 side), and
The paper is discharged to the outside of the main body 31 by paper discharge rollers 29 and 30.

By the way, conventionally, when performing the above-mentioned process, as shown in FIG. 3, rollers (1B), 17, 21, (22) that have no particular purpose such as registration alignment are used.

23, (24), 29, (3G) (Rollers in parentheses are driven), photosensitive drum 1, transfer roller 4, fixing roller 4, upper and lower fixing rollers 14, 15, etc. are the same without stopping or rotating, which would cause problems with printing. The rotation was done at the right time. This was done in order to simplify the mechanism of the drive system as much as possible, and also because it was thought that the printer could respond more quickly to signals from the host side if the photoreceptor was not stopped.

(Problem to be solved by the invention) However, with recent technological innovations, photosensitive drums with smaller diameters are increasingly being used, and in low-speed devices, the process unit section shown in Figure 2 Photosensitive drum 1. Cartridges in which the cleaner 5, charger, or developer 3 are integrated into a single cartridge have come to be used, and because of their short circumference, the photosensitive The lifespan of the drum has come to play a large role in the system. In particular, when a cartridge is used, it is important to match the lifespan of the photosensitive drum with other units such as a cleaner, charger, or developer. When considering an apparatus having a single-sided printing function in such a situation, it has been found that if the photosensitive drum is driven in accordance with the conveyance system as in the past, this will shorten the life of the photosensitive drum.

In other words, the life of the photosensitive drum is limited by the photosensitive layer on the surface being scraped by contact with the cleaner 5, etc., but this scraping can be avoided by driving the photosensitive drum in accordance with the conveyance system. This is because the time it takes to rotate in the contact state becomes unnecessarily long, and the rotation progresses even further. - As an example, OP of photosensitive drum diameter φ30 inner layer
Using a C-drum, the device configured as shown in Figure 2 can perform one-sided continuous printing, one-sided intermittent printing, double-sided intermittent printing,
We will discuss the cases in which each of these is performed. First, in the case of single-sided continuous printing, when the process speed is set to 30 x π ■■, the time required for one rotation of the drum is 1.00 seconds, and if the distance between each paper is 50 - rin for A41 paper. , the time required for each sheet T1 is T+ = C297+50) / 30π = 3.8
Consider the case of 0-order, single-sided intermittent printing, which takes 8 seconds.

Figure 3 shows the timing of each component that makes up the device in double-sided intermittent printing.
Consider the case of single-sided intermittent printing using the s3 diagram. The pre-rotation process requires the longer of the time for the photosensitive drum I to rotate once or twice in order to smooth the photosensitive drum potential, or the time from the operation of the pickup roller 9 to the time for transporting the transfer paper to the transfer section. In the example in Figure 1s2, the latter is a little longer because the photosensitive drum 1 has a small diameter 1, and as a post-rotation step in Figure 3, which took 2.0 seconds, the photosensitive drum l is also rotated in order to smooth the photosensitive drum potential. The longer of the time it takes for 1 to 2 rotations, or the time it takes for the transfer paper to pass through the transfer roller after image writing is completed, and then to be ejected from the machine via the paper ejection rollers 29 and 30. It takes. In the example shown in FIG. 2, the latter was slightly longer at 3.7 seconds. Therefore, 1
The required time T2 per sheet is T2 = 2.0 + 3.7 + 2117/30
π=8.85 seconds. In contrast, consider the case of intermittent printing on one side. In addition, in FIG. 2, the conveyance system includes registration rollers 12, 13, . Fixing exit roller 16°1
7. It is composed of transport rollers 21, 22, 23, 24°, two-sided paper feed rollers 27, 28, and a transport path connecting these. In this conveyance system, the first and second sides of the transfer paper are exchanged. Then, this exchange, that is, the transfer paper passes through the transfer roller 4, goes around the conveyance system once, and returns to the transfer roller 4 is expressed as 1 → 2 sides.
→The second side shall be sent non-stop. This corresponds to the timing chart in FIG. Here, the transport time from the 1st to the 2nd side is as follows, including the switchback time: 15.
It took 0 seconds. Therefore, the time required for l・two-sided printing T
3 is T3 = T2 + 15.0 = 23.85 seconds (time per page for this station).In general, the lifespan of the photosensitive drum is mainly due to scratching of the photosensitive layer due to contact with cleaners, etc. It is often a deviation, therefore it depends on the rotation speed of the photoreceptor. In the OPC drum with a diameter of 30mm in this example, when the thickness of the photoreceptor layer is set to about 22JLm, when the above-mentioned one-sided single-sheet printing (hereinafter referred to as one-sheet intermittent printing) is repeated, It was possible to print approximately 4,000 sheets. By the way, when setting the lifespan of cartridge type products, it is common to set intermittent printing of one page as the worst case.
A cartridge with a lifespan of 4,000 sheets when printing one sheet intermittently is called a cartridge. However, when such a cartridge is applied to a duplex machine, in the above example, 4000X 8.85/(23,85÷2) = 29
89 sheets, which reduces the lifespan to less than 3,000 sheets.In fact, after processing the first side, printing may be stopped once, restarted, and then printed on the second side.In this case, the above-mentioned case Since a post-rotation process is added to the process, the life is further reduced. For this reason, in devices where the photosensitive drum is used independently from other units, the frequency of replacing the photosensitive drum increases, and when the photosensitive drum is integrated with a unit such as a cleaner, charger, or developer. In a type of device that forms a cartridge using a drum, the cartridge may become unusable due to the life of the drum, even if the cleaner or charger is still usable or there is toner remaining in the developer. It has been found that this causes an inconvenience in that it becomes impossible to achieve the number of printable sheets that should be guaranteed. In order to extend the life of the photosensitive drum, there is a method of increasing the thickness of the photosensitive layer, but this tends to cause new problems such as sensitivity and potential stability. However, like the photosensitive drum, consumable parts such as the fixing roller 14, 15 and the transfer roller 4 are driven while in contact with other components, and if such driving is performed unnecessarily, the life of the drum will be shortened. This invention was made in view of the above problems.
It is an object of the present invention to provide an image forming apparatus in which the life of a photoreceptor or a fixing means is not reduced due to unnecessary driving that is performed while a photoreceptor or fixing means is in contact with other components.

(Means for Solving the Problems) A first aspect of the present invention is to form an electrostatic latent image on a photoreceptor,
After this electrostatic latent image is visualized by a developing means, the developed image is transferred onto a supplied transfer sheet using a transfer means, the transfer sheet is discharged, and a cleaning means is applied to the photoreceptor after the transfer. An image forming apparatus that uses a photoreceptor by reversing it after a cleaning process in which it is brought into contact with the photoreceptor, and in which the first side and the second side of the transfer sheet are exchanged in a conveyance system that supplies and discharges the transfer sheet. In an image forming apparatus that performs printing, the transport system is driven between the time when a developed image is formed on the first surface of the transfer sheet and the time when the developed image is formed on the second surface of the transfer sheet. The image forming apparatus is provided with a control unit that performs drive control that provides a photoreceptor stop period in which the photoreceptor is stopped while the photoreceptor is being driven.

Further, the second invention is to transfer the developed image formed on the image carrier onto a supplied transfer sheet using a transfer means, and then fix the developed image on the transfer sheet by a fixing means to fix the developed image on the transfer sheet. In an image forming apparatus that performs double-sided printing by exchanging the first and second sides of the transfer sheet in a conveyance system that supplies and discharges the transfer sheet, the fixing means includes two It consists of book rollers and performs heat fixing or pressure fixing by sandwiching a transfer sheet, and after completing the fixing process on the first side of the transfer sheet, the fixing process is performed on the second side of the transfer sheet. The image forming apparatus includes a control unit that performs drive control that provides a fixing roller stop period during which the fixing unit is stopped while driving the conveyance system until a process is started.

Further, the third invention forms an electrostatic latent image on a photoreceptor, develops the electrostatic latent image into a developed image using a developing means, and then transfers the developed image onto a supplied transfer sheet using a transfer means. An image forming apparatus that performs transfer, ejects the transfer sheet, brings a cleaning means into contact with the photoreceptor after the transfer, cleans the surface of the photoreceptor, and uses the photoreceptor repeatedly, the image forming apparatus comprising: supplying and ejecting the transfer sheet; In an image forming apparatus that performs double-sided printing by exchanging the first side and the second side of the transfer sheet in a conveyance system, there is provided a release means that can release the cleaning means from contact with the photoconductor, and a release means that can release the cleaning means from contact with the photoreceptor; An image forming apparatus comprising a control means for controlling the cleaning means to temporarily release the cleaning means from contact with the photoreceptor after completing the cleaning process and to bring the cleaning means into contact with the photoreceptor again before starting image formation on the second side. be.

(Function) Regarding the first invention, it is not necessary to continuously drive the photoreceptor from the time when a developed image is formed on the first surface of the transfer sheet until the developed image is formed on the second surface, which is wasteful. There is a period when it is driven by By controlling this period to be a photoreceptor stop period in which the photoreceptor is stopped, it is possible to prevent the photoreceptor from being driven unnecessarily while in contact with the cleaning means and shortening its life.

Regarding the second invention, similarly to the photoreceptor of the first invention, the period during which the fixing means is driven in vain is set as the fixing roller stop period, and it is possible to prevent the service life from being shortened as in the prior art. That is, the life of the fixing means, which is composed of two rollers and performs heat fixing or pressure fixing with the transfer sheet sandwiched therebetween, can be extended if the time for which the rollers are driven in contact with each other is short.

Regarding the third invention, the reduction in the life of the photoreceptor is mainly caused by driving the photoreceptor while the cleaning means is in contact with the photoreceptor. After the completion of the process, the contact of the cleaning means with the photoreceptor is temporarily released until the image formation on the second side starts. This makes it possible to avoid shortening the life of the photoreceptor.

(Embodiment 1) FIG. 1 is a timing chart showing an embodiment of the first invention of the present invention. Further, FIG. 4 is a transmission system diagram of each drive system at this time, and the part numbers in FIGS. 1 and 4 correspond to those in FIG. 2. The operation of this embodiment will be explained according to FIG.
First, in the pre-rotation process I, as detailed in FIG. 5(a), the main motor is turned on and the photosensitive drum 1. The pickup roller 9 starts rotating, and after a slight delay, the charger 2
turns on. Then, the transfer paper, which is a transfer sheet, is fed to the registration rollers 12 and 13 by the paper feed roller 1O, and is synchronized with the image signal. The rotation up to this point is called pre-rotation, and printing of the first side is performed as the next step. (The printing operation and image formation have been described in detail when explaining the conventional example, so they are omitted here.) Next, after the first side printing process is completed, a post-rotation process shown in FIG. 6(a) is started. In the post-rotation process, after the laser has finished writing the image on the first side, that is, the image signal OF
After F, first turn off the charger 2A. Next, turn off the bias of the fixing roller at a predetermined timing (not shown).
F F L , after the charger ZAI is turned OFF, the pre-exposure device 2B is turned OFF when the photosensitive drum 1 is rotated after the photosensitive drum 1, and the drive of the photosensitive drum 1 is stopped. At this time, the main motor continues to rotate, and the drive of the photosensitive drum is stopped by cutting off the transmission from the main motor using clutch A shown in FIG. In Figures 1 and 2, once the transfer paper is switched back and the 1st and 2nd sides are replaced, the previous rotation process H
to go into. Here, as shown in FIG. 5(b), the photosensitive drum 1 starts rotating by turning on the clutch A again, and almost at the same time, the charger 2A is turned on. After the photosensitive drum l has rotated approximately once,
The image signal starts writing the image on the second side, and the registration rollers 12 and 13 synchronize the image with the transfer paper.
The face printing process is started. When the image printing on the second side is completed, the process enters the post-rotation process H as shown in Fig. 6(b), and turns off the image signal, charger, main motor, etc. in sequence.
Now, when printing 192 pages using the sequence described above, when conveying from l to 2 pages, the conventional example shown in Fig. 3 takes 15.0 seconds as the paper conveyance time for the 1st and 2nd page. In contrast, in the embodiment shown in FIG.
→The rotation time T4 of the photosensitive drum l during two-sided conveyance is
T4 = (back rotation) + (front rotation ■) ◆ (second side printing process time) = 1.3 + 1.2 + 297/30π = 5.
85 seconds, 15.0-5 in L/2-sided print
J5 = The rotation time of the photosensitive drum l could be shortened by 9.35 seconds. Therefore, the rotation time T5 of the photosensitive drum 1 during printing on two sides is as follows.

Ts = T3 -9.35 = 14.5 seconds, and the printing time per page is 7.25 seconds, which is kept to the same level or less than the printing time T2 = 8.85 seconds when one page is intermittent. I was able to do it.

In this example, the time required for the front and rear rotation processes is as follows: front rotation process ■> front rotation process ■, rear rotation process I and rear rotation process ■; This is because the time required to process the paper is longer than the time required to equalize the potential of the photosensitive drum 1, causing the photosensitive drum 1 to rotate for an unnecessarily long time. Therefore, Fig. 5(a), Fig. 6
Instead of FIG. 7(b), as shown in FIGS. 7(a) and 7(b), the rotation of the photosensitive drum 1 is started late and stopped early.
By changing the post-rotation process, the life of the -layer photosensitive drum 1 can be extended.

Further, in this embodiment, the effect of reducing the amount of deviation of the photosensitive drum 1 was mainly explained, but at the same time, the effect of reducing the amount of deviation of the photosensitive drum 1 was explained.
It also prevents unnecessary charging of the image, and is also effective in preventing image blurring in high humidity environments caused by adhesion of ozone products and the like.

In one or more embodiments, the transfer roller 4 is driven by the photosensitive drum 1, so the sequence is the same as that of the photosensitive drum 1. However, even if the photosensitive drum 1 and the transfer roller 4 are driven separately, It goes without saying that both should have the same timing in terms of sequence because of the relationship in which they rotate in contact.

(Example 2) FIG. 8 and FIG. 9 show an example of the second invention.
The photosensitive drum L is driven by a dedicated drum motor, and the fixing roller 14 is driven by a clutch H.
10 FF. And the ninth
As shown in the timing chart in the figure, the main motor O
After N, the drum motor is turned ON and the photosensitive drum 1 etc. starts rotating at the timing shown in FIG. Start the printing process for the first side. After the first side printing process is completed, the post-rotation process starts at the timing shown in FIG. 7(b) described above, and the photosensitive drum 1 is stopped.Next, after the transfer paper passes.

The driving of the fixing roller 14 is stopped. Hereinafter, for the second side, turn the fixing roller 14 ON10F in the same manner.
F. By controlling the drive system in this manner, it is possible to extend the life of not only the photosensitive drum 1 but also the fixing roller 14, and there are also effects described below.

(1) Generally speaking, the load on the fixing roller is larger than that of other conveyance systems, so the stiffness at the time of 0N10FF is easily transmitted to other drive systems. However, by driving the photosensitive drum 1 with a dedicated motor, The rotation of l is the fixing roller 1
It is not affected by the 0N10FF of 4.

(2) By making the ON timing of the fixing roller 14 precede the rotation of the registration roller 12 (when it is OFF, the fixing roller 14 is naturally turned OFF after the registration roller 12 has stopped), the 0N10 of the fixing roller 14 is
It is possible to prevent the rotation of the registration rollers 12 from being influenced by the FF.

According to (1) and (2), in order for the fixing roller 14 to release the contact with the fixing roller 15, 0N10FFL,
However, it is possible to prevent the image from being distorted due to the shock caused by the fixing roller's 0N10FF.

(Embodiment 3) FIG. 10 shows an embodiment of the third invention. In FIG. It is something. At this time, since the cleaner 5 is designed to rotate around the shaft 36, the solenoid 33 is set to 0FFL, and the spring 3
When the pressure applied by the cleaner 5 is released, the cleaner 5 moves in a direction away from the photoreceptor l. In Fig. 11, 0 of solenoid 33 is shown.
N10 FF O of solenoid 33, indicating F timing
In order to prevent the shock from being transmitted to the image when the cleaner 5 is pressed against the photosensitive drum 1 due to N, the solenoid 33 needs to be turned on before the image signal is written. Also, even when it is OFF, the image on the photosensitive drum l is transferred onto the transfer paper by the transfer roller 4, and then the solenoid 3
Turn 3 off. By controlling pressurization and release of the cleaner 5 in this manner, the effects described below are produced.

(1) The time period for which the cleaner 5 is brought into contact with the photosensitive drum l is
Since the rotation time of the photosensitive drum 1 described in the first or second embodiment can be further reduced, it is possible to further suppress the displacement of the photosensitive drum 1 due to contact with the cleaner 5 (first embodiment).
(Compare Figure 1 with Figure 1 or Figure 9).

(2) By releasing the contact with the cleaner 5, the life of the photosensitive drum 1 itself will not be impaired even if the photosensitive drum 1 is rotated for a long time. Therefore, the photosensitive drum 1 can be driven at the same timing as the main motor, for example. This makes it possible to easily control the drive system.

Note that the third embodiment described above is similar to the first embodiment. It may be used in combination with the second embodiment. In this case, the amount of deviation of the photosensitive drum 1 can be further suppressed, and the charging time for the photosensitive drum l can also be shortened. This has the effect of making it difficult for image blurring to occur due to adhesion of ozone products and the like onto the drum.

(Effects of the Invention) As explained above, according to the present invention, in a copier or printer that applies electrophotography and has a single-sided printing function, the photoreceptor is driven at a predetermined timing during operation of the device. By stopping the photosensitive drum (first invention) and releasing the cleaning means from contact with the photosensitive drum (fourth invention), unnecessary driving of the photosensitive member can be reduced and shortening of the life span can be prevented. Especially photoconductor and other process units/),
For example, in a cartridge type device that integrates a cleaning means, a charging device, a developing device, etc.

It is possible to obtain an economical effect in that the lifespan of each process unit can be made uniform and the lifespan of the cartridge itself is not impaired even when double-sided printing is performed.

Further, while the device is in operation, the drive of the fixing roller is also stopped at a predetermined timing in the same way as the photoreceptor (second invention).
By doing so, the life of the fixing roller, which is a consumable item, can be extended, and the life of the entire apparatus and maintenance intervals can be extended.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the driving timing of each component constituting the image forming apparatus according to an embodiment of the first invention, and FIG. Overall schematic sectional view of beam printer, 3rd
The figure shows the operation timing of the components constituting the device in a conventional image forming apparatus, FIG. 4 is a drive transmission system diagram in the embodiment of the first invention, and FIG. 5(a) is the front view of FIG. 1. A timing diagram showing the rotation process l in more detail,
FIG. 5(b) is a timing diagram showing in more detail the pre-rotation step Ⅰ in FIG. 1, FIG. 6(a) is a timing diagram showing the post-rotation step I in FIG. ) is a timing diagram showing the post-rotation process (■) in detail in Fig. 1, Fig. 7(a) is a timing diagram further improving the timing of Fig. 5(a), and Fig. 7(b) is a timing diagram showing Fig. 6 in detail. 8 is an explanatory diagram showing a drive transmission system of an image forming apparatus according to an embodiment of the second invention, and FIG. 9 is an operation of the components shown in FIG. 8. FIG. 10 is a schematic diagram showing the main parts of an image forming apparatus according to an embodiment of the third invention;
FIG. 11 is a timing diagram showing the timing of operation of the components in the 10th embodiment. Explanation of symbols l...Photosensitive drum (photosensitive member) 2A...Charger 2B...Pre-exposure device 3...
・Developer 4...Transfer roller (transfer means) 5...Cleaner (cleaning means) 6...Laser scanning optical system 7...Reflection mirror 8...Paper cassette 9...
・Pickup roller 10.11... Paper feed roller 12.13... Registration roller 14.15... Fixing roller 16.17... Fixing exit roller 18A, 18B... Flapper 19.20... Conveyance guides 21.22, 23.24...conveyance rollers 25.26
... Half-moon roller 27.28 ... Two-sided paper feed roller 29.30 ... Paper ejection roller 31 ... Printer body 33 ... Solenoid 34 ... Pressure plate 35 ...
Spring 36...Rotating shaft Fig. 4 Fig. 6 (03 Post-rotation odor presentation I (b) flit discharge worker female ■ Fig. 5 Main (=, -tar)
(ONrjjn Fig. (0) Front movable knee aIl (b) A-knee rotation process ■1 Fig. 8<j+1!Movement I?, continuous" l full times> Fig. 10

Claims (3)

[Claims] (1) After forming an electrostatic latent image on a photoconductor and making this electrostatic latent image visible by a developing means, the developed image is transferred onto a supplied transfer sheet using a transfer means, and the transferred image is An image forming apparatus that discharges a sheet and repeatedly uses a photoconductor through a cleaning process in which a cleaning means is brought into contact with the photoconductor after transfer, wherein the transfer system is used to supply and discharge the transfer sheet. In an image forming apparatus that performs double-sided printing by exchanging the first and second sides of a sheet, a developed image is formed on the first side of the transfer sheet, and then a developed image is formed on the second side of the transfer sheet. An image forming apparatus comprising: a control means for performing drive control that provides a photoreceptor stop period in which driving of the photoreceptor is stopped while driving the conveyance system until the image forming apparatus is formed. (2) An image in which the developed image formed on the image carrier is transferred onto a supplied transfer sheet using a transfer means, and then the developed image on the transfer sheet is fixed by a fixing means and the transfer sheet is discharged. The first side and the second side of the transfer sheet are formed by a conveyance system which is a forming device and which supplies and discharges the transfer sheet.
In an image forming apparatus that performs double-sided printing by switching sides, the fixing means is made up of two rollers and performs heat fixing or pressure fixing with the transfer sheet sandwiched between them, and the fixing means is configured to perform heat fixing or pressure fixing by sandwiching the transfer sheet, and fixes the image onto the first side of the transfer sheet. A fixing roller stop period is provided between the end of the fixing process and the start of the fixing process on the second side of the transfer sheet, during which the fixing roller stops driving while the conveyance system is driven. An image forming apparatus characterized by comprising a control means for performing drive control. (3) After forming an electrostatic latent image on the photoreceptor and making this electrostatic latent image visible using a developing means, the developed image is transferred onto a supplied transfer sheet using a transfer means, and the transferred image is transferred. An image forming apparatus that ejects a sheet, brings a cleaning means into contact with the photoreceptor after the transfer has been completed, cleans the surface of the photoreceptor, and uses the photoreceptor repeatedly, and a conveyance system that supplies and ejects the transfer sheet. In an image forming apparatus that performs double-sided printing by exchanging the first and second sides of the transfer sheet, the image forming apparatus includes a release unit that can release the cleaning unit from contact with the photoreceptor, and a process for cleaning the image on the first side. An image forming apparatus comprising: a control means for once releasing the cleaning means from contact with the photoreceptor after the cleaning has been performed, and then controlling the cleaning means to come into contact with the photoreceptor again before starting image formation on the second side. .