JPH04133957A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain paper in the order according to pages by providing timing rollers in front of a combination part of each of carrier paths for sending out the paper toward a combination part so that the paper sent out from each of the carrier paths overlaps each other at the combination part and an interval is made between the paper and the paper succeeding it. CONSTITUTION:A combination part 30 is provided for combining carrier paths 31 and 32 of paper ejected from each image forming unit. In front of the combination part 30 of each of the carrier paths 31 and 32, timing rollers 33 and 34 are provided for sending out the paper toward the combination part 30 so that the paper sent out from each of the carrier paths 31 and 32 overlap each other at the combination part and an interval is made between the paper and the paper succeeding it. By this, the paper ejected from each of the image forming unit is ejected after overlapping each other at the combination part 30 in the order according to pages, and as the interval is made between the paper and the paper succeeding it, the paper ejected from each of the image forming unit does not overlap each other unexpectedly out of order.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an image forming apparatus such as a printer, and more particularly to an image forming apparatus that includes a plurality of image forming units and uses them in combination to form an image. It is related to.

(Prior art) In recent years, printers that use laser beams, LEDs, etc. as light sources,
While there is an increasing demand for high-end models with added functions such as double-sided printing, composite printing, color printing, and sorting, there is also an increasing demand for single-function, inexpensive and compact models. Very compact devices are emerging.

In Japanese Patent Laid-Open No. 63-246754, the present applicant has previously disclosed that a plurality of image forming units are stacked vertically, and an upper and lower image is formed by a paper transport unit having a switching means capable of switching the paper transport path. An image forming apparatus has been proposed in which a paper feeding section and a paper discharging section of a forming unit are connected to each other.

According to this image forming apparatus, it is possible to provide a double-sided printing function, a composite printing function, a color printing function, etc. by passing the paper through a plurality of image forming units in various ways in a paper transport unit, and also to It is also possible to form images in each of the forming units.

(Problems to be Solved by the Invention) Incidentally, the image forming apparatus disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 63-246754 has multiple image forming units share the task of forming a series of images on a plurality of sheets, and performs simultaneous and parallel image formation. Since this configuration does not aim to speed up image formation, if a series of image formation is divided among multiple image forming units, the sheets on which images have been formed will need to be arranged in a page-aligned state. However, there is a problem in that complicated page alignment work is required after image formation.

In view of the above-mentioned conventional problems, the present invention has been developed so that even when a series of images on a plurality of sheets are divided into a plurality of image forming units and images are formed in parallel at the same time, the sheets on which images have been formed are arranged in page alignment. The object of the present invention is to provide an image forming apparatus that can be obtained.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an image forming apparatus including a plurality of image forming units, in which a merging section joins the transport paths of sheets discharged from each image forming unit. is installed at a position before the merging section of each transport path, so that the sheets sent out from each transport path are overlapped at the merging section and a gap is provided between the sheets and the following sheets. The invention is characterized in that it is equipped with a swimming roller that sends out the water.

(Function) Since the present invention has the above-mentioned configuration, each image forming unit performs image formation on a predetermined page according to the order in which sheets are stacked at the merging section. Since the sheets are ejected after being overlaid on top of each other in page order at the merging section, and there is a gap between the sheets that follow, it is possible for the sheets ejected from each image forming unit to overlap unexpectedly, resulting in pages being misaligned. It is possible to obtain sheets of paper on which images are formed by each image forming unit in a state in which the pages are aligned.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 3.

In FIG. 1, la and lb are upper and lower image forming units stacked vertically, each consisting of a single-function, small-sized printer; The paper refeed port is connected to the lower paper transport unit) 21b interposed between these image forming units) la and 15, and the upper paper transport unit is also connected to the upper image forming unit) la. ) 21a is installed.

In each image forming unit 1a, lb, a laser beam modulated by an image control section (not shown) and emitted from a semiconductor laser 2 is main-scanned by a polygon mirror 3, and
An image is formed on the photosensitive drum 10 via the correction lens 4 and the folding mirror 5.

Further, the photoreceptor drum 10 is charged by a charger 11,
A latent image is formed by a laser beam, developed by a developing device 12, transferred onto the paper by a transfer charger 9, and residual toner is removed by a cleaner 13.

Paper is fed by a paper feed roller 7 from paper feed cassettes 6a and 6b installed in each image forming unit (1a) and 1b, respectively, and the fed paper is transferred to a register roller 8 to form an image on a photosensitive drum 10. The image is conveyed to the transfer section at the same time. The paper transferred by the transfer section is fixed by the fixing section 14, and is ejected from the paper ejection port by the ejection roller 15. Note that the upper image creation unit 1a has a paper feed power
A refeeding roller 16 is provided at a refeeding port in the lower part of a to receive the paper discharged from the paper transport unit 21b and supply it to the register roller 8. Of course, the lower image forming unit 1b may also be provided with the paper refeed roller 16 to standardize the image forming unit.

The paper conveyance units 21a and 21b are provided with a vertical conveyance path 22 and a horizontal conveyance path 23, which convey the paper discharged from the paper discharge roller 15 upward. A discharge roller 24 is provided to discharge the paper onto the paper discharge trays 25a and 25b.

A branching claw 26 is provided at the upper end of the rising conveyance path 22 of the lower paper conveyance unit) 21b, and a bypass path 27 and a horizontal conveyance path 2 that go straight upward on the rising conveyance path 22 are provided.
It is branched into 3. The paper that has proceeded straight through the bypass path 27 is discharged from the lower paper transport unit 21b and is fed to a joining portion 30 of the upper paper transport unit 21a with the lower end of the rising transport path 22. Further, a branch claw 28 is provided at a position in front of the ejection roller 24 on the horizontal transport path 23 of the lower paper transport unit 21b, and the paper is ejected to the paper ejection tray 25b via the ejection roller 24 or via the delivery roller 29. The configuration is such that it is possible to switch whether or not to feed the sheet to the refeed roller 16 of the upper image forming unit 1a. Note that the upper paper conveyance unit 21a has a branch claw 26 and a bypass path 2.
7. A chair provided with a branch claw 28 and a delivery roller 29;
Although the lower paper transport unit l-21b is not provided with the merging section 30, the paper transport unit may be standardized by compensating for the deficiency in both.

A merging section 30 provided in the upper paper conveyance unit) 21a
As shown in FIG. 2, the upper image forming unit 1
a first conveyance path 31 that conveys the paper discharged from the merging section 30 toward the rising conveyance path 22; A second conveyance path 32 is provided for conveying the paper supplied to the upper paper conveyance unit l-21a via the upper conveyance path 22 and the bypass path 27 toward the upright conveyance path 22 via this merging section 30. , and the first
First and second timing rollers 33 and 34 are provided in front of the confluence of the and second conveyance paths 31 and 32, respectively,
Furthermore, paper sensors 35 and 36 for detecting the presence or absence of paper are arranged in front of the paper sensor 35, 36. In addition, in Fig. 2, 22a
are conveyance rollers appropriately provided on the upright conveyance path 22.

Next, referring to FIG. 3, an explanation will be given of the operation when forming a series of images on a plurality of sheets is divided into the upper and lower image forming units 1a and 1b to simultaneously form images in parallel.

The upper image forming unit) Ia is for odd-numbered pages of paper ■, ■,
The lower image forming unit 1b takes charge of image formation for even-numbered sheets of paper ■, ■, and so on.
The image formation is performed in sequence at almost the same timing so that the images ``and'', ``and'', ``■'' and ``■'', ``■'' and ``...'' are superimposed. The sheets ■ and ■ that were first image-formed and discharged in the upper and lower image forming units 1a and 1b are conveyed to the first and second conveyance paths 31 and 32, and are conveyed to the paper sensor 35 before the merging section 30. After its existence was confirmed in .36, Fig. 3 f
As shown in a), the timing rollers 33 and 34 send the signals to the merging section 30 at a timing such that they overlap each other. The degree of overlap is adjusted by timing rollers 33 and 34. Next, as shown in FIGS. 3(b) and 3(C), the sheets ``■'' and ``■'' are conveyed along the upright conveyance path 22 in a superimposed state at the merging section 30. These sheets (2) and (2) then pass through the horizontal conveyance path 23 and are placed on the sheet discharge tray 25a by the discharge roller 24 from below with the image forming surface facing downward.
, ■ are discharged in the order. On the other hand, sheets ■ and ■ on which subsequent images have been formed arrive at the first and second conveyance paths 31 and 32 of the merging section 30, and these sheets also overlap each other at the timing rollers 33 and 34. It is sent to the confluence section at such timing.

The degree of overlap between these sheets ■ and ■, ■ and ■, etc. is set within a range that allows for a space to be provided between the trailing edge of the preceding sheet ■, ■ and the leading edge of the following sheet ■, ■. . This prevents overlapping between the preceding sheet and the following sheet, and prevents page irregularities from occurring due to unexpected overlapping. After that, as shown in FIG. 3(d), the paper ■,
2 are overlapped at the merging section 30 and conveyed through the upright conveyance path 22, and the subsequent sheets 2 and 3 reach the first and second conveyance paths 3132, and similarly the timing roller 33
．． At step 34, the sheets are sent to the merging section 30 so as to overlap with each other, and the above operation is repeated thereafter, images are formed on the final page, and the sheets are sequentially ejected to the sheet ejection tray 25aJ=.

In this way, the upper and lower image forming units la and 1b share the image formation on the sheets of paper, which are placed on the paper discharge tray 25a with the image forming side facing downward, and sequentially from the bottom.
The sheets can be discharged with the pages aligned as shown in (2), and the sheets can be discharged with the pages aligned while a plurality of image forming units share the task of forming a series of images on a plurality of sheets.

The present invention is not limited to the above-mentioned embodiment. For example, in the above-mentioned embodiment, the case where there are two image forming units is illustrated, but it is also possible to use three or more image forming units, and in that case, even if they are stacked together. , may be divided into several stages and overlapped. Furthermore, although a laser printer has been shown as an example of the image creation unit, it is also applicable to thermal transfer printers, inkjet printers, and the like.

(Effects of the Invention) According to the image forming apparatus of the present invention, as is clear from the above description, each image forming unit forms an image on a predetermined page according to the order in which sheets are stacked at the merging section. As a result, the sheets ejected from each image forming unit are stacked on top of each other in page order at the merging section and are ejected, and a gap is provided between the sheets that follow, so that the sheets ejected from each image forming unit To achieve the effect that sheets on which images are formed by each image forming unit can be obtained in a state in which the pages are aligned, without the sheets being unexpectedly overlapped in between and resulting in uneven pages.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a schematic overall configuration diagram, FIG. 2 is a configuration diagram of the confluence of the paper discharge paths, which is the main part, and FIG. 3(a) -(d) are operation explanatory diagrams. 1 a------------ Upper image forming unit 1
b----------1.-Lower image forming unit 30
---1---------- Merging section 31--------1-------First conveyance path 32---111111 Second Conveyance route 33---
・−・−1−−−−−First timing roller 34−
--1・---1---Second timing roller. Agent Patent Attorney Masaru Ishihara

Claims (1)

[Claims] (1) In an image forming apparatus equipped with a plurality of image forming units, a merging section is provided for merging the transport paths of sheets ejected from each image forming unit, and a merging section is provided in front of the merging section of each transport path for each transport. An image forming apparatus characterized by being provided with a timing roller that sends out sheets of paper toward a merging section so that the sheets sent out from the path are overlapped with each other at the merging section and a gap is provided between the sheets and the following sheets. .