JPH0325461A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the dislocation of images formed on both sides of a recording medium by comparing an image forming area set to the recording medium with an actual image forming area of the recording medium, where an actual image is formed, and subordinately correcting a subsequent image transfer area of the recording medium. CONSTITUTION:A recording sheet 8 used for forming an image on a first side is fed from a paper feed cassette 6, and a resist roller 9 adjusts the timing of writing an image to transfer an image. Then, a light projector 18 disposed in a prescribed position between a fixing unit 13 and a photosensitive body 1 irradiates light, whose reflected light is received by a photodetector 19 and inputted to an arithmetic circuit 100a. The arithmetic circuit 100a obtains a distance between the trailing edge of the recording sheet 8 and a ruled line through prescribed counting operation. The timing of forming an image on the back of the recording sheet 8, that is, the recording medium is corrected, and the image positions on both sides of the recording sheet 8 are associated with each other. Consequently, the transparent dislocation of the first and second images can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus capable of printing a predetermined format image on one or both sides of a recording medium.

(Prior Art) FIG. 9 is a cross-sectional view illustrating the configuration of a conventional image forming apparatus. Reference numeral 1 denotes a photoreceptor, which rotates at a predetermined speed in the direction of the arrow. ON/OFF
The modulated light beam is deflected and scanned via a polygon mirror 4. A primary charger 2 uniformly charges the surface potential of the photoreceptor 1. A developing device 5 visualizes the electrostatic latent image formed on the photoreceptor 1 using a developer (toner). Reference numeral 6 denotes a paper feed cassette that stores recording paper serving as a recording medium in a stack. Reference numeral 7 denotes a paper feed roller, and the paper feed roller 7 is driven to feed the recording paper 8 to the position where the registration rollers 9 are arranged. 1
o is a transfer charger that transfers the toner image visualized on the photoreceptor 1 onto the recording paper 8; A cleaner 11 collects toner remaining on the photoreceptor 1. A pre-exposure lamp 12 exposes the entire surface of the photoreceptor 1 to remove electric charge. Reference numeral 13 denotes a fixing roller (fixing device) which heats and presses the toner image transferred to the recording paper 8 to fix it onto the recording paper 8. Reference numeral 14 denotes a flapper that switches the conveyance direction of the recording paper 8 between paper ejection and duplex/multi-processing direction.

A switchback flapper 15 switches the conveyance direction of the recording paper 8 conveyed via the conveyance guide toward the refeeding tray 17 or from the refeeding tray 17 toward the refeeding guide 17a. Note that 16 is a paper refeed roller.

In the apparatus configured in this way, after the primary charger 2 uniformly charges the photoreceptor 1 driven at a predetermined speed, a light beam emitted from the laser 3 is applied to the surface of the photoreceptor 1 using a polygon mirror. -4 to scan. The laser 3 is turned on/off according to image information by a controller (not shown), and is applied to the photoreceptor 1 without a static beam. A latent image is formed. The developing device 5 visualizes the electrostatic latent image, and the developing method is as follows:
This is done by reversal development that causes toner particles to adhere to the area irradiated by the laser 3. The developed image thus formed on the photoreceptor 1 is synchronized by a registration roller 9 between the recording sheets 8 which are taken out one by one by a sheet feeding roller 7 from a stack of recording sheets 8 held in a sheet feeding cassette 6. The image is then melded together and transferred onto the recording paper 8 by the transfer charger 10.

The residual toner on the photoreceptor 1 is collected by the cleaner 11, and the cleaned surface of the photoreceptor 1 is uniformly exposed over the entire surface by the pre-exposure lamp 12 to remove the surface potential and be used for the next image formation. used.

The recording paper 8 onto which the developed image has been transferred is heated and pressed by a fixing device 13, so that the toner image is permanently fixed on the recording paper 8. In the case of single-sided printing, the flapper 14 is located at the dotted line position in the figure, and the recording paper 8 is ejected outside the machine.

In the case of double-sided printing, the flapper 14 is located at the position shown by the solid line, and the recording paper 8 is advanced by the intermediate conveyance roller and sent to the paper refeed tray 17 via the switchback flapper 15 located at the position shown by the solid line.

When a print signal for the second side is sent from a host computer (not shown), the recording paper 8 is fed out by the paper refeed roller 16, switched back by the switchback flapper 15 located at the dotted line position, and then the registration roller 9
leading to.

The second developed image is formed on the photoreceptor 1 in the same manner as the first one, and then transferred by being superimposed on the second surface of the recording paper 8 which is synchronized by the registration rollers 9. Thereafter, the completed double-sided print passes through the fixing device 13 and is discharged to the outside of the machine by the flapper 14 located at the dotted line position.

The above image forming process is performed by the controller.
The sequence is controlled by the timing shown in Figure 0.

FIG. 10 is a timing chart illustrating the control operation of the image forming apparatus shown in FIG. 9.

As can be seen from this figure, when the print signal PRI is commanded, the controller starts the sequence and the laser 3
Wait for the charging by the primary charger 2 to become stable before writing out the image information. The laser 3 starts writing after 1 second, repeats on/off for a time τ 1 second depending on the image size, and finishes writing one page with the laser 3. The registration roller 9 sends a print signal PR! in synchronization with the development image being sent to the transfer area. Therefore, it operates after two seconds and feeds out the recording paper 8. Paper feed roller7. Both the paper refeed rollers 16 operate at an early point after the print signal PRI so as to finish feeding the recording paper 8 to the position where the registration rollers 9 are placed before the registration rollers 9 start operating.

(Problem to be Solved by the Invention) However, the writing start time τ of the laser 3 for both the first side and the second side. and the time difference Δτ=τ2−τ of 2 between the start time of the registration roller 9 and the start time of the registration roller 9. is set to a constant value, so when forming a format image with double-sided printing, the ruled lines on the first and second sides may shift, causing the ruled lines from the front side of the recording paper 8 to change from the back side, or from the back side to the front side. Figure 11(a). As shown in (b), there is a problem in that the character information inside the ruled lines becomes very difficult to see.

FIG. 11 is a schematic diagram illustrating format printing deviation during double-sided printing, with (a) showing the front side and (b) showing the back side.

In these figures, A indicates the leading edge of the recording paper 8, and B
indicates the trailing edge of the recording paper 8, C indicates the left edge of the recording paper 8, and D indicates the right edge of the recording paper 8. a - d are the outermost frame lines of the ruled lines, and the outermost frame line b should be formed at a distance ML from the tip side A, but corresponds to the state where it is actually formed at a distance 11tL1, Further, the outermost frame line b, which should be formed at a regular distance of 11 m from the rear end side B, corresponds to a state where it is formed at a distance m1. Arrow U in the figure indicates the conveyance direction.

In addition, in forming an image on the back side, the rear end side B in FIG. 12A corresponds to the state in which the leading end side B1 becomes the leading end side B1, and the leading end side A in FIG. a11, bit indicates the outermost frame line. In addition, the dotted lines in FIG.
With the recording paper 8 of 0 to 100 gr/m2, the image on the back side is visible, so especially when ruled lines of the same format are printed on the front and back sides, a problem arises in that the misalignment between the two becomes unsightly. That is, when writing with the laser 3, the positions of the outermost frame lines a and b are counted and written using the image clock, with the leading edge A of the recording paper 8 having an assumed size as a reference. Although the distance between the leading edge A and the outermost frame line a is relatively small, the distance between the leading edge A and the outermost frame line (ruled line) b is approximately 300 mm for A4 size and approximately 400 mm for A3 size, and the optical System magnification. Due to errors in the rotational speed of the photoreceptor 1, image clock, etc., the outermost frame line b (indicated by the dashed line in the figure), which should originally be formed at a distance of 11L from the tip side A, is now at a distance of 1iiL1. The outermost frame line b1 is formed at the position (in the figure (a), the relationship L<Ll holds true). In this case, the distance between the trailing edge B and its nearest ruled line is m
Despite this assumption, in reality, ml (same figure (
In a), the relationship m>m1 holds true. The magnitude of this shift amount Δlm-mll is as large as 3 mm at maximum for A4 size and 4 mm at maximum for A3 size, assuming a magnification error of 1% on the image.

As shown in FIG. 6B, when printing on both sides, the trailing edge B of the front surface becomes the leading edge B1, and the ruled line b1 on the second side is the same as the outermost frame line b on the first side. It is written at a distance @m from the tip side B1, which is the reference side, assuming that it has been printed. However, in reality, the outermost frame line b on the first side is 1 distance from the rear edge B! Since it is formed at a distance of i(tml), it will appear shifted when viewed through.

Whether the distance 11 aml becomes larger or smaller with respect to the distance m depends on the image magnification λ specific to the image forming apparatus.
) shows a nearly constant value for each device,
It can be assumed that it does not change over time. The influence of the image magnification λ becomes larger as the ruled line is farther from the reference side, the trailing edge B in FIG. 12A and the trailing edge A1 in FIG.

This invention was made in order to solve the above problems, and compares the image forming area set on the recording medium with the real image forming area formed on the recording medium and transfers the image to the subsequent recording medium. By performing area dependent correction, it is possible to accurately prevent misalignment of double-sided images formed on recording media, and it is also possible to suppress variations in the actual image forming area of each recording medium and obtain recorded images with uniform print format. The purpose is to obtain an image forming apparatus that can perform the following steps.

(Means for Solving the Problems) An image forming apparatus according to the present invention includes a detection means for detecting the image position of an image transferred onto a recording medium, and a subsequent and a first correction means for correcting the image forming timing for the recording medium that is fed.

Further, the first correction means is configured to correct the scanning timing of the optical scanning system and the development timing of the developing means in conjunction with each other.

Further, the first correction means is configured to correct the feeding timing of the recording medium and the transfer timing by the transfer means in conjunction with each other.

In addition, the image forming timing for the back side of the recording medium is corrected depending on the image position on the front side of the recording medium detected by the conveyance means for conveying the recording medium so as to form images on both sides of the recording medium and the detection means. A second correction means is provided.

(Function) In this invention, when the image position of the image transferred onto the recording medium is detected by the detection means, the first correction means corrects the image formation timing for the subsequent recording medium, and the subsequent feeding is performed. To make it possible to match an image start position of a recording medium with an image start position of a preceding recording medium.

Further, at this time, the first correction means corrects the scanning timing by the optical scanning system and the development timing of the developing means in conjunction with each other, and corrects the image start position of the recording medium that precedes the image start position of the recording medium to be subsequently fed. It is possible to match the

Furthermore, at this time, the first correction means corrects the feeding timing and the transfer timing by the transfer means in conjunction with each other, so that the image start position of the subsequently fed recording medium matches the image start position of the preceding recording medium. make it possible.

Further, when the recording medium on which single-sided image formation has been completed is conveyed by the conveying means so that the opposing surface of the recording medium becomes the image forming surface, the second correction means detects an image of the surface of the recording medium. It is possible to correct the image formation timing for the back side of a recording medium depending on the position and match the positions of opposing images on the same recording medium.

(First Embodiment) FIGS. 1(a) and 1(b) are a cross-sectional configuration diagram and a block diagram showing an example of an image forming apparatus according to a first embodiment of the present invention, and are the same as FIG. 9. The same symbols are given to the same numbers. Note that the apparatus is shown as a double-sided printer capable of forming images on opposing surfaces (both sides) of recording paper 8 serving as a recording medium.

In these figures, 18 is, for example, a laser beam or LE
D (light emitting diode). A light irradiator consisting of a light irradiator and the like irradiates the image formed on the recording paper 8 being conveyed with light. 19 is a photodetector consisting of a photodiode etc.
The reflected light emitted from the light irradiator 18 and reflected on the white background portion of the recording paper 8 being conveyed is received, and the light reception signal α is sent to the control circuit 1.
00 arithmetic circuit 100a. The control circuit 100 is composed of an arithmetic circuit 100a and a controller section 100b (consisting of a CPU, ROM, RAM, etc., not shown), and constitutes the first correction means of the present invention. When the image position of the image transferred to is detected by the detection means (comprised from the light irradiator 18 and the light detector 19), the first correction means corrects the image forming timing for the subsequent recording paper 8. , it is possible to match the image start position of the subsequently fed recording paper 8 to the image start position of the preceding recording paper 8.

In addition, at this time, the first correction means interlocks the scanning timing of the optical scanning system (in this embodiment, configured from the above 3.4, etc.) and the developing timing of the developing device 5, which is the developing means, as will be described later. Then, the image start position of the subsequently fed recording paper 8 is made to coincide with the image start position of the preceding recording medium.

Next, the operation in FIG. 1 will be explained in detail with reference to FIGS. 1(C) and 1(d).

FIG. 1(C) shows the arithmetic circuit 100 shown in FIG. 1(b).
FIG. 12 is a characteristic diagram illustrating the characteristics of the light-receiving signal α input to a, and the same or equivalent parts as in FIG. 11 are given the same reference numerals.

FIG. 1(d) is a timing chart illustrating the operation timing of each part shown in FIG. 1(a).

Recording paper 8 is fed from paper cassette 6 to form an image on the first side, and when the image writing timing is adjusted by registration rollers 9 and the image is transferred, it is sequentially conveyed in the direction of the arrow. At this time, the recording paper 8 is transferred to the fixing device 13, for example.
A light irradiator 18 disposed at a predetermined position between the photoreceptor 1 and the
When light is irradiated and the reflected light is received by the photodetector 19, a light reception signal α shown in FIG. 1(b) is input to the arithmetic circuit 100a.

At this time, the arithmetic circuit 100a calculates the distance 11 Jtml between the trailing edge B of the recording paper 8 and the ruled line b1 by a predetermined counting process, and stores it in the internal memory on the subsequent recording medium (in this case, the same as the recording paper 8). feedback data (correction value Δ
m=lm-mll). In this embodiment, the scanning start timing of the laser 3 (from the print signal manual input to the time τ0 is determined by the time Δτ
. ) is corrected as shown in FIG. 1(d), and the developing device 5 also adjusts the time Δτ in conjunction with this correction.

The minute drive timing is pre-corrected (the solid line shown in FIG. 1(d) corresponds to the timing after correction, and the broken line corresponds to the timing before correction).

As a result, the positions of opposing images on both sides of the same recording paper 8 match, the positions of format images (for example, ruled line images, tabulation images) match, and it becomes possible to eliminate watermark misalignment between upper and lower images.

Note that if the size of the recording paper 8 that is continuously fed is not changed, that is, if the format ruled line pattern of the same layout is to be printed continuously on the recording paper 8 of the same size, when printing both sides of the first sheet, Obtained correction value Δm
It may be configured such that the value is held and used as the value of the second side for the second and subsequent sheets. Also, if the size of the recording paper 8 is different,
If the distance 11jjfL from the outermost frame line b of the trailing edge B to the leading edge A is different, the distance lint for the first side may be detected each time, and the correction value Δm for the first side may be determined.

Further, in the above embodiment, a case has been described in which the first correction means corrects the laser 3 and the developing device 5 in conjunction with each other according to the correction value Δm detected by the detection means, but as shown in FIG. , the conveyance timing and transfer timing of the recording paper 8 may be corrected in conjunction with each other.

[Second Embodiment] FIG. 2 is a timing chart illustrating the correction process by the control circuit 100 shown in FIG. 1(b). In addition,
Components that are the same as those in FIG. 1(a) are given the same reference numerals.

Further, the solid lines in the figure correspond to the values after correction, and the broken lines correspond to the values before correction.

As can be seen from this figure, the first correction means corrects the feeding timing (driving timing of the registration rollers 9 in the figure) and the image transfer timing (
This makes it possible to match the drive timing of the transfer charger 10 with the image start position of the preceding recording medium.

That is, the time Δτ is set so that the image position on the second side advances in the traveling direction of the recording paper 8, with the time point at which the registration roller 9 starts operating on the second side. Time delayed by minutes Δτ. The sequence of the transfer charger 10 is also delayed by Δτ0 minutes as a whole.

In this way, when performing the same correction process, the correction time increases when correcting the registration roller 9 system and when correcting the scanning timing of the laser 3 as shown in the first embodiment. For example, it can be divided into a direction (slowing down) or a negative direction (speeding up), so for example, time. is very short, i.e. when starting the image sequence with an instant start and a wait time of approximately rQJ, then τ0 - Δτ. Therefore, it is assumed that the correction becomes impossible. Therefore, in such a case, a correction that delays the sequence of the registration roller 9 by Δτ0 may be selected. On the other hand, when it is necessary to perform a correction to advance the sequence of the registration rollers 9, if the recording paper 8 has not reached the registration rollers 9, the correction may not be performed accurately. Therefore, in such a case, the same effect can be achieved by selecting a correction that delays the writing sequence of the laser 3 as shown in FIG. 1(d).

Therefore, if it is difficult to correct only the writing timing of the laser 3 or only the registration roller 9 due to the device configuration, depending on the sign of the deviation amount (m-m1),
In the case of m<m1, the writing timing of the laser 3 is changed to Δ
By delaying by τ0 minutes, and in the case of m>m1, by delaying the drive timing of the registration roller 9, the feedback system for the amount of deviation may be switched to match the image forming positions.

In the above embodiment, the case where alignment is performed only in the conveyance direction of the recording paper 8 has been explained, but as shown in FIGS. A light irradiator 18b and a photodetector 19b are provided at orthogonal positions, and the distance n1 between the left edge C of the recording paper 8 and the outermost frame C is detected, and the main scan writing tie is determined for the following recording paper 8. By correcting the image shape position also in the direction orthogonal to the transport direction as explained in the above embodiment, it is possible to match the top and bottom image positions of format images such as tabulations or ruled lines, for example, when forming double-sided images. This makes it possible to prevent vertical watermark misalignment of the image.

[Third Example] Figure 3(a). (b) is a schematic diagram illustrating the image position detection process in the main scanning direction in the image type detection device according to the third embodiment of the present invention. photodetector 19b
are provided facing each other perpendicularly to the conveyance direction of the recording paper 8.

FIG. 4 is a characteristic diagram showing the characteristics of the light reception detection signal α1 output from the photodetector 19b shown in FIG. 3(a).

As can be seen from this figure, when the photodetector 19b detects the left edge C of the recording paper 8, the light reception detection signal α1 rises, and when the ruled line C is detected from the left edge C, the light reception detection signal α1
becomes the L level, and the main scanning timing for the subsequent recording paper 8 is corrected based on this distance @nl. Note that to the right of the distance [nl, the received light detection signal α1 changes over time depending on the image, but the distance 11 [tnl] between the left end side C and the outermost frame line C varies greatly. do not have. Therefore, the time average value over one page of recording paper can be adopted as the value of distance lint, but the distance lint at a specific time
The value of nt may be set to the print distance 111nl.

FIG. 5 is a signal processing circuit diagram of the light reception detection signal α1 output from the photodetector 19b shown in FIG. 3(a), and the same components as in FIG. 1(b) are given the same reference numerals. It has been done.

When the light reception detection signal α1 is input to the arithmetic circuit 100a,
The value ni of the distance 11 inl on the first surface and the designed distance lin
The difference Δnl (Inl−no l) between the values no of t is calculated. The timing correction signal β is output to the driver of the laser 3.

The light emission of the laser 3 is transmitted from the arithmetic circuit 1 ooa to the controller unit 100 by counting the time from a well-known beam detection point BD for each scan of the photoreceptor 1.
Information on the positive/negative sign of the difference Δnl, n, -no is output to b. When printing the second side, when the laser 3 emits light, the time from the beam detection point BD to the laser emission is corrected by Δτ 10 seconds as shown in FIG. )),
The distance from the left edge C of the recording paper 8 on the second side to the outermost frame line C is the same as that on the first side.

In each of the first to third embodiments, the distance between the edge of the recording paper 8 on the first side and each corresponding ruled line is used as a reference value, and the corresponding distance on the second side is corrected. However, this is not limited to double-sided printing devices, and the measured value of the first side is used as a design value, and the distance on the second side is the distance between the edge and the corresponding ruled line when printing on one side. If applied instead, the accuracy of the ruled line position on the recording paper 8 for single-sided printing will be improved, that is, the variation in the ruled line position on the recording paper 8 that has been sequentially discharged and completed the single-sided printing will be eliminated, and the printing quality will be improved.

In the above embodiment, the image position on the first side formed on the recording paper 8 is detected, and the image position on the second side or the subsequent recording paper 8 is subjected to dependent correction to suppress variations in ruled line printing positions, etc. As explained above, one sheet of recording paper 8
A means for the operator to directly set and input the printing position deviation amount of the double-sided print result, for example, a correction amount volume 20.21 shown in FIG. The correction process may be configured to be executed in the main scanning direction orthogonal to the transport direction.

[Fourth Embodiment] FIG. 7 is a plan view illustrating an example of an operation unit in an image forming apparatus showing a fourth embodiment of the present invention. In (a), 20 indicates a correction amount volume, and an index - The correction amount in the transport direction can be set in units of 1 mm for each step from 4 to 4.

In (b), 21 indicates a correction amount volume, and the correction amount in the main scanning direction can be set in units of 10lII1 for each step from index -4 to 4.

FIG. 8 is a flowchart showing an example of the image forming position correction processing procedure according to the present invention, including (1) to (7).
indicates each step.

First, wait for the print signal to be input (1)
When the print signal is input, feed the recording paper 8 (2
). Next, one of the recording sheets 8 output from the photodetector 19
When the light detection partner number α for face value is input to the arithmetic circuit 100a, (3) feedback data (correction value Δm
=lm-nil) and (4) send the laser 3 driver to start scanning (time τ from print signal manually).
. up to in time Δ. ) as shown in Figure 1(d) (5) Wait for the print signal for the second side (6) When the print signal is input, start the print sequence for the second side.7 ) When printing is finished, exit IA Chiri.

〔Effect of the invention〕

As explained above, the present invention includes a detection means for detecting the image position of an image transferred onto a recording medium, and a detection means for detecting the image position of an image transferred onto a recording medium, and a detection means for detecting an image position of an image transferred onto a recording medium, and a detection means for detecting an image position of an image transferred onto a recording medium. Since the first correction means for correcting the image formation timing is provided, when forming images of the same format on a recording medium, the ruled line formation positions on the recording paper can be made uniform, and the output appearance can be improved.

In addition, since the first correction means is arranged to correct the scanning timing of the optical scanning system and the development timing of the developing means in conjunction with each other, it is possible to sufficiently The image forming position can be corrected with a margin, and the image forming position for each recording medium can be corrected with high accuracy, so that the ruled line positions can be made uniform.

Furthermore, since the first correction means is configured to correct the feeding timing of the recording medium and the transfer timing by the transfer means in conjunction with each other, in an apparatus that starts an image sequence with an instant start and a wait time of approximately rQJ, printing is possible. Even in a situation where the sequence must be delayed, it can be handled with sufficient margin by correcting the feeding timing of the recording medium, and the image forming position for each recording medium can be corrected with high precision to make the ruled line positions uniform.

It also includes a conveyance means for conveying the recording medium so as to form images on both sides of the recording medium, and an image forming tie control for the back side of the recording medium depending on the image position on the front side of the recording medium detected by the detection means. Since the second correction means for correction is provided, images in the same format can be maintained at the same position on both sides of the recording medium without any positional deviation. Therefore, there are excellent effects such as fewer image watermarks caused by misalignment of the upper and lower image positions, and easier identification of the image on the target surface of the recording medium.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are a cross-sectional configuration diagram and a block diagram showing an example of an image forming apparatus according to a first embodiment of the present invention, and FIG. 1(d) is a characteristic diagram illustrating the characteristics of the light-receiving signal α manually inputted to the arithmetic circuit shown in FIG. This figure is a timing chart explaining the correction IA filling by the control circuit shown in FIG. A schematic diagram illustrating the direction image position detection process, FIG. 4, is similar to FIG.
) is a characteristic diagram showing the characteristics of the light reception detection signal output from the photodetector shown in FIG. 5, and FIG. 5 is a signal processing circuit diagram of the light reception detection signal output from the photodetector shown in FIG. , 6th
5 is a timing chart illustrating the operation of FIG. 5, FIG. 7 is a plan view illustrating an example of an operation section in an image forming apparatus according to a fourth embodiment of the present invention, and FIG. 8 is an image forming apparatus according to the present invention. FIG. 9 is a sectional view illustrating the configuration of a conventional image forming apparatus; FIG. 10 is a timing chart illustrating control operations of the image forming apparatus shown in FIG. 9; , FIG. 11 is a schematic diagram illustrating format printing deviation during double-sided printing. In the figure, 18 is a light irradiator, 19 is a photodetector, 100 is a control circuit, 100a is an arithmetic circuit, and 100b is a controller section. Figure 1 (C) (d) Iris') *>k 1Urib Replace the controller? Figure 4 Figure 5 Figure 100 Cause 8 Figure 6 Figure TI. 1o Δtlo U1o m]210 Fig. 7 (a) (b) Pull to the left Fig. 9 Boot signal Fig. 10 Fig. 11

Claims (4)

[Claims] (1) An optical scanning system that forms an optical image on the photoreceptor, a developing means that visualizes the electrostatic latent image formed on the photoreceptor by the optical scanning system, and a developing means that develops the electrostatic latent image on the photoreceptor. an image forming apparatus having a transfer means for transferring a developed image onto a conveyed recording medium, a detection means for detecting an image position of an image transferred onto the recording medium, and an image detected by the detection means; An image forming apparatus comprising: a first correcting means for correcting image forming timing for a recording medium that is subsequently fed depending on the position. (2) The image forming apparatus according to claim 1, wherein the first correction means corrects the scanning timing of the optical scanning system and the development timing of the developing means in conjunction with each other. (3) The image forming apparatus according to claim (1), wherein the first correction means corrects the feeding timing of the recording medium and the transfer timing by the transfer means in conjunction with each other. (4) A conveyance means for conveying the recording medium so as to form images on both sides of the recording medium, and image formation on the back side of the recording medium depending on the image position on the front side of the recording medium detected by a detection means. The image forming apparatus according to claim 1, further comprising a second correction means for correcting timing.