JPS6149660B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for controlling the feeding timing of a recording material in an image forming apparatus such as a copying machine. In particular, the present invention relates to a feeding control device that controls the relative position of an image formed on a recording material and the recording material to a fixed position.

A feeding control device in a transfer type electrophotographic copying machine will be explained below as an example. Conventionally, in order to align the leading edge of the image formed on the photoconductor through exposure and development with the leading edge of the transfer paper, a predetermined rotational position of the photoconductor is detected and a feeding roller is operated to transfer the transfer material to the transfer station. It was something to send.

However, since the start of the optical system or document table that moves back and forth to scan the photoreceptor for exposure is not always constant, the latent image is not necessarily formed at a fixed position on the photoreceptor. The disadvantage was that the leading edge of the image was shifted. In order to solve this drawback, there is a system that detects the specific position of the optical system or the movement path of the document table to operate the feeding roller, but in this case, the feeding timing is determined by the reciprocating movement of the optical system or the document table. During this period, there were restrictions. Therefore, it could not be applied to a copying machine that transfers images independently of exposure scanning.

The present invention eliminates the above-mentioned drawbacks and provides a feeding control device suitable for a copying apparatus that transfers images onto a plurality of transfer materials in one exposure scan.

That is, the present invention includes a recording body that rotates repeatedly, a reciprocating scanning unit that exposes and scans an original, an image forming unit that forms an image corresponding to the original on the recording body, and a plurality of transfer materials that are repeatedly moved to a transfer position. A feeding means for feeding, a transfer means for transferring an image on the recording medium onto the transfer material at the transfer position, and an information signal regarding an image forming position on the recording medium while the scanning means is scanning the document. a storage means for storing a predetermined time; and a control means for repeatedly controlling the feeding timing of the feeding means using the information signal from the storage means to align the image on the recording medium with the plurality of transfer materials. The present invention provides a feeding control device consisting of the following.

Here, it is also possible to set the memory by directly detecting the tip of the latent image with a potential measuring device or the like. Furthermore, when image exposure is performed while the original (sheet) itself is being transported, it is also possible to set the memory by detecting the transport position of the original itself. The position detection can be performed by operating a micro switch, photoelectric element, or Hall element provided on the moving path by a cam, a light emitter, or a magnet provided on the document table or optical system. The position of the original itself can be detected by activating the above-mentioned microswitch on the original, but by detecting the reflected light from the light emitter provided on the travel path.

Examples will be described below with reference to the drawings. FIG. 1 is a sectional view of a screen type copying apparatus to which the control device of the present invention can be applied.

In the figure, 11 indicates a housing surrounding the device,
A manuscript such as a presentation or a document is placed on a manuscript table 12 made of a transparent member such as glass on the upper part of the housing 11. This document mounting table 12 is of a fixed type, and image irradiation onto a screen drum 13, which will be described later, is performed by partially moving an optical means. This optical means is already well known, and the first mirror 14 and document illumination lamp 15 move at a speed V over the entire distance of the placement table 12 from the solid line position to the leftmost chain line position. On the other hand, at the same time as the first mirror 14 moves to scan the mounting table 12, the second mirror 16 moves at a speed of V/2 from the solid line position to the leftmost chain line position. The original image obtained by the scanning of the first and second mirrors 14 and 16 is irradiated onto the screen drum 13 whose circumferential speed is V via a lens system 17 having an aperture mechanism and a fixed mirror 18. Ru. The screen drum 13 is made of a mesh drum in which a photoconductive layer is provided on a conductive layer, and a transparent insulating layer is further provided on the photoconductive layer. It's like that.

The drum 13 rotates in the direction of arrow F, and a latent image forming means is arranged near the drum 13 along the direction of rotation of the screen drum 13. That is, 20 is a corona discharger which is a primary voltage applying means, and charges the rotating screen drum 13 to a sufficient voltage. Reference numeral 21 denotes a corona discharger serving as a secondary voltage applying means, which forms a primary electrostatic latent image by irradiating the original image while eliminating the charge on the screen drum 13 caused by the discharger 20. For this reason, the structure of the discharger 21 is such that the shield plate on the back side is optically open. Reference numeral 22 denotes a lamp for illuminating the entire surface of the screen drum 13, which uniformly irradiates the screen drum 13 with light to rapidly increase the electrostatic contrast of the primary electrostatic latent image. By the above means, a primary electrostatic latent image with high electrostatic contrast is formed on the screen drum 13. The primary electrostatic latent image thus formed on the screen drum 13 is formed as a secondary electrostatic latent image on the insulating drum 24 which is rotated in the direction of arrow M by the modulated corona discharger 23. Note that the insulating drum 24 is the conductive support 2
5 is coated with an insulating layer 26, and a voltage is applied between the conductive support 25 and the conductive member of the screen drum 13, and the modulated corona ions are transferred to the insulating layer 26.
By guiding it to the surface, the secondary electrostatic latent image is formed. The secondary electrostatic latent image formed on the insulating layer 24 as described above is developed into a toner image by a known liquid type or dry type developer (developing means) 27. Thereafter, the toner image is transferred at a transfer position 28 to a transfer material (paper sheet) 29 that has been conveyed in synchronization with the toner image. After the insulating drum 24 has undergone the transfer process, residual toner on the insulating layer 26 is removed by a cleaner (cleaning means) 30 using a known blade or brush, and the surface potential is made uniform by a corona discharger 31. Prepare for copying process.

The transfer material 29 to be conveyed to the transfer position 28 is loaded in a first cassette 32 and a second cassette 42, and is moved by delivery rollers 33 and 43, respectively.
and separated one by one by separation claws 34, 44,
The toner image is conveyed by register rollers 35 in accordance with the toner image position. 36 is a corona discharger for transfer, and is a discharger for applying a bias voltage to the transfer material 29 when transferring a toner image. After the transfer, the transfer material 29 is separated from the insulating drum 24 by a separation belt (not shown), reaches the fixing device 38, where the toner image is fixed by the fixing roller 39, and transported to the finished transfer material storage tray 41 by the conveyor belt 40. be done. In the above-mentioned copying apparatus, once a primary electrostatic latent image is formed on the screen drum 13, a secondary electrostatic latent image is formed from this primary electrostatic latent image. There is no need to scan the original again when making a copy.

Therefore, when making multiple copies, it is only necessary to operate the steps after the formation of the secondary electrostatic latent image. Therefore, in this step, the rotational speed of the screen drum 13 is set to be lower than that during the formation of the first latent image, for example. This can be doubled, increasing the copying speed.

FIG. 2 is a schematic diagram extracted from FIG. 1 only for the parts necessary for registering the copy paper during transfer. 45 is a micro switch for detecting the stop position (initial position) of the document platen, which is installed in the document platen movement path to determine the feeding timing of the copy paper. A signal is generated by passing a cam provided in the system (hereinafter, this position will be referred to as a registration position). 46 is a micro switch for detecting the final forward position of the optical system (hereinafter referred to as the reversal position); 47 is a micro switch for detecting the stop position of the photosensitive drum 13, which is activated by a cam provided at the reference position P of the photosensitive drum 13; Operate. 48 is a clutch (hereinafter referred to as a register clutch) for applying a rotational driving force to the register roller 35 in synchronization with the photosensitive drum 13; A is the position where the image light is incident on the photosensitive drum 13; and B is the primary position on the photosensitive drum 13. A position where ions are modulated by the latent image to form a secondary latent image on the insulating drum 24, C is a position where the leading edge of the powder image on the insulating drum 24 and the leading edge of the copy paper 29 contact and are transferred, and D is the register roller 35. The position where the copy paper 29 temporarily stops at the contact point of the upper and lower rollers, T ₀ is the distance (time) that the optical system moves from the stop position (OHP) 44 to the registration position 45 . _T1 is the time from when P of the photosensitive drum 13 passes the drum stop position 47 until the optical system reaches the optical system registration position 45 (FIG. 4). T ₂ is the distance from the copy paper stop position D of the register roller 35 to the insulated drum 2.
This is the distance (time) that the copy paper moves to the contact position C on 4.

FIG. 3 is a drive circuit diagram of the resistor clutch 48.
FIG. 4 is an operation time chart of the circuit.
50, 51, 52, 53 in Figure 3 are general R-
In the S flip-flop circuit (hereinafter referred to as FF),
A level “1” (hereinafter referred to as 1) input to S outputs 1 to Q and 0 to Q, and then 1 input to R outputs Q,
It inverts the output of 60 and 61 are three-digit up counter circuits, the clock terminal is the input terminal for the pulses to be counted, R is the reset terminal,
Q ₁ , Q ₁₀ , Q ₁₀₀ are 1, 10, and 100 digits, respectively.
Each has 4 signal lines with BCD output terminals. This counter 60 stores the registration time.
1 measures the time until registration. 62 is a coincidence detection circuit for checking the coincidence between the counters 60 and 61, which compares the digital signals inputted to A ₁ , A ₁₀ , A ₁₀₀ and B ₁ , B ₁₀ , B ₁₀₀ , so that A ₁ =B ₁ , A ₁₀ =
When B ₁₀ , A ₁₀₀ = B ₁₀₀ , 1 is output from the output terminal out. 63 is a general differentiation circuit consisting of a resistor and a capacitor for detecting the rise of a signal; 6
4 is an interface (amplifier) circuit that converts the output of the FF53 into a drive signal for the register clutch.

In FIGS. 3 and 4, DHP is a drum stop position detection signal, and CP is a series of clock pulse signals generated in synchronization with the photosensitive drum 13 (for example, a disk connected directly to the photosensitive drum 13 that rotates in synchronization with the rotation of the drum). (obtained by optically detecting a large number of holes in the hole). RG is a registration position detection signal, and TES is a signal indicating that modulation is in progress, which is generated at 1 from the start of modulation to the end of copying (END) by a sequence control circuit (not shown). END is a signal indicating the end of copying, and is a pulse that generates 1 when a predetermined number of sheets have been copied by a sequence control circuit (not shown). CLOFF is a signal for turning off the register clutch, and is a pulse generated when the clock CP is counted by a sequence control circuit (not shown), that is, when the photosensitive drum 13 rotates by a predetermined angle. FAD is a signal indicating that the optical system is moving forward, and the optical system is moving forward to form a primary image by a sequence control circuit (not shown). In the time chart of FIG. 4, α indicates the amount of change when the time T ₀ for the optical system to move from the stop position 44 of the optical system to the registration position 45 changes.

Explain the operation of the circuit. In the circuit diagram of Figure 3, 5
When the power is turned on, each of the FFs 0, 51, 52, and 53 is reset by a general power-up preset circuit (not shown), and their Q outputs are 0 and outputs are 1. Similarly, counters 60 and 61 are also reset, and all outputs become 0. When copying is started by turning on the copy button CPB in this state, the photosensitive drum 13 and the insulating drum 24 begin to rotate, and accordingly, a clock pulse CP is generated, which is applied to one input terminal of the AND gates 56 and 57. join.
But each is connected to the other input terminal.
Since FFs 51 and 52 have been reset and 0 has been input, both outputs remain at 0. In this state, all outputs of counters 60 and 61 are 0,
The A input and B input of the matching circuit 62 are equal, and 1 is output from the out terminal. Therefore, one input of the AND gate 58 becomes 1, but the other input is the signal being modulated.
Since TES is still 0, FF 53 is never set and register clutch 48 does not operate. At this time, if the optical system is not at its stop position 44, another control circuit (not shown) moves the optical system to the second position.
Move it in the direction opposite to the arrow in the figure and stop at the stop position 44.
to stop it. Meanwhile, the optical system is at resist position 45.
However, since the optical system advance signal FAD input to one of the AND gates 54 is 0, its output remains 0. Further, even if the reference position P of the photosensitive drum 13 passes the drum stop position 47, if the optical system is not at the stop position 44, one input of the AND gate 59 is 0, so its output remains 0.
Next, when the optical system is at its stop position 44 and the photosensitive drum rotates until the reference position P reaches the drum stop position 47, all inputs to the AND gate 59 become 1, and its output changes from 0 to 1. . Accordingly, the FF circuit 51 is set and its output Q changes from 0 to 1. As a result, one input of the gate 56 becomes 1, and its output outputs a signal in response to the clock pulse CP. Counter 60, connected to the output of gate 56, therefore starts counting clock pulses CP. Further, as the photosensitive drum passes the stop position of the reference position P, the sequence control circuit CT (b in FIG. 3) starts counting clock pulses CP and starts on/off control of the process processing means in a preprogrammed order. When the photosensitive drum 13 continues to rotate and its reference position P rotates 150 degrees from the drum stop position, the optical system forward clutch is turned on by the control circuit CT, and the optical system starts moving forward from the stop position 44. . Then, when the optical system reaches the resist position 45 after T ₀ time has passed from 150°, the gate 54
Both inputs become 1, and its output changes from 0 to 1 for the first time, resetting and inverting the FF circuit 51. Accordingly, the gate 5 to which the Q output is connected
Since one input of gate 56 becomes 0, the gate 56 becomes 0 from then on regardless of the clock pulse CP input to the other gate.
is not output. In addition, another FF 50 is set and inverted at the same time, and the gate 59 to which its output is connected is closed, and the FF circuit 51 remains set until the FF circuit 50 is reset again by the copy end signal END, that is, unless the output becomes 1. There's nothing to do. That is, the counting of clock pulses that started from passing the drum stop position 47 is stopped when the optical system passes the register position 45, and the counter 60 stores the count value until then until a reset signal is applied to the R terminal. , during this time
Output from the Q ₁ , Q ₁₀ , and Q ₁₀₀ output terminals. That is, at the time when the leading edge of the image light enters the photosensitive drum 13, the reference position P of the photosensitive drum 13 is at the drum stop position 47.
It is stored as a count value indicating the rotation angle after passing through.

Further, the photosensitive drum 13 continues to rotate, completing the formation of one electrostatic latent image on its surface, and at point B in FIG. 2, a modulated image is formed on the insulating drum 24 by the electrostatic latent image. When the modulation starts, that is, when the photosensitive drum reaches the second rotation of 260 degrees on the time chart in FIG. Then, when the photosensitive drum 13 continues to rotate and its reference position P reaches the position indicated by ○A on the time chart in FIG.
Modulation starts from the tip of the latent image. When the third drum stop position signal DHP is applied to one input of the gate 55, its output produces the DHP signal since the other input terminal is already 1. Thereby
The FF circuit 52 is set, and the gate 57 to which its output terminal Q is connected begins to output a clock pulse CP. That is, the counter 61 to which the output of the gate 57 is connected starts counting clock pulses. Thereafter, a three-digit BCD signal is output according to the number of clock pulses counted and applied to the B input terminal of the matching circuit 62. When the counter 61 counts the number of clock pulses equal to the stored value of the counter 60, the signal at the output terminal OUT of the digital signal matching circuit 62 changes from 0 to 1 and is applied to one input of the gate 58. Since the modulating signal connected to the other input of gate 58 is 1 at this time, FF circuit 53 is set. As a result, the Q output of the FF circuit 53 changes from 0 to 1, and the resist clutch 48 is turned on via the output circuit 64.

Also, the change in the Q output is applied as a differential signal to the R terminal of the FF circuit 52 via the differentiating circuit 63.
Reset the circuit. Furthermore, this signal is sent to counter 6
It also applies to the R terminal of 1, resets the counter 61 to 1, and sets its outputs Q ₁ , Q ₁₀ , and Q ₁₀₀ to all 0.
In other words, in the time chart of Fig. 4, after the reference position P of the photosensitive drum passes the drum stop position in the third rotation, the resist clutch is operated after counting the number of clock pulses equal to the aforementioned _T1 hour. At the same time, the clock pulse count is stopped and the counter 61 is reset.

As a result, the copy paper 29, which has been conveyed by the feed roller 33 driven by the sequence control circuit CT and is stopped at point D of the register roller 35, is sent out as the register roller 35 rotates. After the photosensitive drum 13 has further rotated for T ₂ hours, the copy paper contacts the insulating drum 24 at point C.
(At point ○A in Figure 4) Align the toner image on the insulating drum with the leading edge. When the photosensitive drum 13 continues to rotate and the P point passes the drum stop position for the fourth time,
Since the FF circuit 52 is set again, the counter 61 starts counting the clock pulses CP. When the clock reaches 150° for the fourth time, the resist clutch off signal is detected.
CLOFF is generated from the sequence control circuit CT,
Since it is added to the R terminal of FF circuit 53, FF circuit 5
Reset 3. As a result, the register clutch 48 is turned off, and feeding of the first copy sheet is completed. At this point, the copy paper is completely separated from the register rollers. Then, the photosensitive drum 13 rotates again, and the stored value of the counter 60 and the counter 61
When the outputs match, the register clutch is turned on again for registration of the second copy sheet. After repeating this operation and completing the copying of a predetermined number of sheets, the modulating signal TES changes from 1 to 0, and furthermore, the copy end signal END is generated from the sequence control circuit CT, and the R of the FF circuit 50 and counter 60 is output. is applied to the terminal, resetting both and completing all operations in preparation for the next copy.

When the next exposure scan is performed, the optical system will move to its stop position 4.
The time to move from 4 to registration position 45 is T ₀
If the reference position P of the _{photosensitive} drum 13 passes the drum stop position 47 and the optical system reaches the registration position 45, the time T ₁
also changes to T ₁ +α, so the counter circuit 60
The number of clock pulses stored in the memory also changes according to T ₁ +α. Therefore, the next timing to turn on the register clutch 48 is after the drum has passed the stop position and after the number of clock pulses corresponding to T ₁ +α has been counted, and the start for exposing the optical system and document table is delayed, and the leading edge of the document image on the drum is delayed. Even if the position of the copy sheet changes, the register clutch operates to compensate for this change, so that the leading edge of the copy sheet and the leading edge of the image can always be aligned. In addition, micro switch 4
It is also possible to shift the leading edge of the image by a predetermined position from the leading edge of the paper by shifting the position of 5 or by slightly adjusting the value of the counter 60.

The screen-type copying machine has been described above, but in a typical copying machine that exposes a photosensitive drum or magnetic drum to form an electrostatic or magnetic latent image, develops the latent image, and transfers the developed image to a transfer material. It is also possible to apply the invention for paper-to-image registration during transfer. In other words, this is effective when the registration roller is driven before the image exposure scan starts or after the scan ends.

As described above, in the present invention, the timing for operating the feeding means is set in advance and stored for a predetermined time so that the leading edge of the transfer material and the leading edge of the image contributing to transfer are in a predetermined positional relationship. Since the operation is controlled, an image can be formed at a predetermined position on a transfer material no matter when the image formation period that contributes to transfer occurs, and even when transfer is performed repeatedly from one image, an image can always be formed at a predetermined position.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a recording device to which the present invention can be applied, FIG. 2 is a schematic sectional view of the feeding control portion of FIG. 1,
3a and 3b are circuit diagrams showing the feeding control device according to the present invention, and FIG. 4 is a time chart showing the operation of FIG. 3. In FIG. 62 is a coincidence circuit for detecting coincidence between counters 60 and 61; 48 is a resist clutch;
DHP is a signal indicating the drum stop position.

Claims (1)

[Claims] 1. A recording body that rotates repeatedly, an image forming means that includes a reciprocating scanning means that exposes and scans a document, and forms an image corresponding to the document on the recording body, and a feeder that repeatedly feeds a plurality of transfer materials to a transfer position. A feeding means, a transfer means for transferring the image on the recording medium onto the transfer material at the transfer position, and an information signal regarding the image forming position on the recording medium during scanning of the document by the scanning means, and storing the information signal for a predetermined period of time. A storage means, and a control means for repeatedly controlling the feeding timing of the feeding means based on the information signal from the storage means in order to align the image on the recording body with the plurality of transfer materials. Feed control device featuring features.